The eastern kingbird (Tyrannus tyrannus) is a large tyrant flycatcher native to the Americas. The bird is predominantly dark gray with white underbelly and pointed wings. Eastern kingbirds are conspicuous and are commonly found in open areas with scattered trees and bushes, where they perch while foraging for insects. The Eastern kingbird is migratory, with its breeding range spread across North America and its wintering range in Central and South America.


The eastern kingbird was described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name of Lanius tyrannus. The present genus Tyrannus was introduced in 1799 by the French naturalist Bernard Germain de Lacépède with the eastern kingbird as the type species. The species is monotypic; no subspecies are recognised.


Adults are grey-black on the upperparts with light underparts; they have a long black tail with a white end and long, pointed wings. They have a red patch on their crown, seldom seen. They are of average size for a kingbird, at 19–23 cm (7.5–9.1 in), 33–38 cm (13–15 in) across the wings and weighing 33–55 g (1.2–1.9 oz).
The call is a high-pitched, buzzing and unmusical chirp, frequently compared to an electric fence.


Some eastern kingbirds place their nests in the open, while others hide their nests well. Eastern kingbirds in southern British Columbia may nest in open fields, in shrubs over open water, high up in trees, and even in the tops of small stumps. Both male and female participate in nest defense, but females may stay on well-hidden nests longer than females with open nests, who may leave nests earlier to chase away predators. Those pairs nesting in the open may be able to see predators coming earlier and rely on aggressive behavior to protect their young.
The aggressive behavior of eastern kingbirds has been shown to keep ravens and crows from finding experimental nests placed near kingbird nests. Similar experimental nests placed further from the kingbird nests were more likely to be spotted by crows and ravens. Blue jays, American crows, squirrels, and tree-climbing snakes are on occasion kingbird nest predators. American kestrels likely prey on the adults.


Eastern kingbirds wait on an open perch and fly out to catch insects in flight, sometimes hovering to pick prey off vegetation. They also eat berries and fruit, mainly in their wintering areas.


The Western Kingbird (Tyrannus verticalis) is a large tyrant flycatcher found throughout western environments of North America, as far south as Mexico.

Adults are a combination of both gray and yellow plumage, along with crimson feathers that are hidden until courtship or against intruders. Characteristic of kingbird species, the Western Kingbird is very territorial. Although the Western is often misidentified as Cassin's kingbird, Couch's kingbird, or the Tropical kingbird due to the yellow coloration, it can be distinguished from these other species through its black, squared tail with white edges.


The breeding habitat is open areas in western North America. The increased presence of trees throughout the Great Plains during the past century due to fire suppression and tree planting facilitated the range expansion of the Western Kingbird, as well as range expansions of many other species of birds.


The song is a squeaky chatter, sometimes compared to a squeaky toy. The call is a sharp loud whit. It occasionally sings before sunrise.


Udaspes folus, the grass demon, is a small but prominent butterfly found in India & Nepal that belongs to the skippers family, Hesperiidae. It is regarded as an occasional pest of ginger and turmeric.


Male. Upperside black, the basal half of both wings covered with minute yellowish scales, markings pure white, semi-hyaline. Forewing with a large white spot filling up the end of the cell, two similar conjoined spots outwardly below it extending from beneath vein 4 to the sub-median vein, hardly separated from each other by vein 2; four conjugated sub-apical spots, the uppermost one minute, two similar spots below them nearer the outer margin, a small spot between these and the two large conjoined spots. Hindwing with a very large medial white patch with its margin sinuous all round; abdominal area covered with yellowish hairs. Underside paler. Forewing with the markings as on the upperside. Hindwing with the white medial patch extending to the abdominal margin from near the costa to one-third above the anal angle, the extension suffused with grey, also extending narrowly to the outer margin, double blackish-brown lunular marks, within the white space at the bases of the sub-median nervules. Cilia blackish, alternated with white. Antennae black; palpi, head and body concolorous with the wings, whitish on the underside, legs brown above, whitish beneath.
Female like the male, but the spots are larger.
— Charles Swinhoe, Lepidoptera Indica. Vol. X
It is a small butterfly with a wingspan of about 4 to 4.8 cm. It is black with a large white spot on the upperside of the hindwing and several smaller whites spots on the forewing. The underside of its wings is mostly white with brown edges and spots.


Not rare in India. Rare or very rare in certain parts of its global range. This butterfly is seen chiefly during the monsoon, perhaps due to its larval host plants growing at this time of the year.


The grass demon is to be found in deciduous and semi-evergreen forests. It prefers the edges of open spaces rather than the deep forest shade or open sunlight. It is most abundant in the more open regions of hilly jungle. It is also encountered on the plains at some distance from such terrain. It occurs up to 8,000 feet (2,400 m) in the hills of South India and up to 5,000 feet (1,500 m) in the Himalayas.


The grass demon prefers forest edges or clearings where dappled light is present. Its black and white colouration may have evolved to take advantage of the dappled light in these areas. The pied pattern which seems prominent in the open is effectively disruptive in the shade and the butterfly is difficult to locate once it settles down.
It is a bold insect and not easily disturbed. It usually flies in the shade among bushes and under trees keeping low and close to the ground. From time to time, it takes short flights, and, occasionally, much longer excursions into the open clearings. Its flight is quick and the path is very erratic making it very difficult to track when in flight.
When basking it sits on the upperside of leaves of herbs or bushes with its hindwings pressed flat against the surface and its forewings held half open at an angle above the hindwings.
This butterfly also has a unique wing flashing display most often seen just after it has alighted on a leaf. It will move its hindwings down toward the leaf surface. When the hindwings are about halfway down the forewings also start moving downwards. On the upward beat both wings are moved simultaneously till the hindwings come together. Then it again begins the downward beat. Each beat is performed very slowly and the butterfly is very conspicuous during this time.
This display is unique since no other peninsular Indian butterfly is known to display the capability of moving forewings and hindwings separately.
The grass demon is a nectar lover and has a long proboscis compared to body size. This makes it easy to get to nectar of flowers with long corolla tubes. In gardens, the common periwinkle (Vinca rosea) and Lantana are its favourite flowers. It rarely visits bird or dung droppings. It is fond of water and often seen perched on a stone in a stream-bed.


The butterflies emerge in February or March and lay eggs before they die. The eggs remain dormant till the rains, that is, usually the month of May, when they hatch. The caterpillars pupate in September and October and the adults emerge four to six months later. In some cases the caterpillars pupate later and in these cases the pupa remain dormant, throughout the dry season, till May when the rains begin.


The female normally sits on the underside of the leaf of the host plant and lays a single egg. The egg is reddish and appears smooth and dome shaped. When about to hatch it turns white with a red top.


Soon after hatching, the caterpillar does not consume the eggshell completely and it makes itself a spacious cell and hides inside it. The caterpillar is sluggish and comes out to feed only at night. Even when disturbed it is reluctant to leave its cell.
The caterpillar is a light uniform leaf green colour with a dark green pulsating line on the back and a relatively small, dark head. The full grown larva has the habit of resting with the first three segments contracted, so as to give a humped appearance. It always lies closely applied to the leaf, by turning over a triangular piece from the edge onto the upper surface over itself. Specific host plants include Zingiber zerumbet.


Pupation takes place on the same plant within a cell. The pupa is long and cylindrical, watery green in colour. It has a long conical projection in front of the head. The eyes are easily seen but do not protrude out of the outline of the pupa. The pupa broadens towards the shoulders and the abdomen gradually tapers to the last segment.
The most striking characteristic of the pupa is its proboscis. It is long and thin generally extending up to and a little beyond the tip of the abdomen. The pupa is the same colour of the caterpillar and unmarked. It is covered in a thin layer of white powder. The body band is neither too tight nor too loose and allows the pupa to wriggle if disturbed.


The grass demon feeds on ginger, turmeric, and their relatives Curcuma aromatica, Curcuma decipiens, Hedychium sp. and other plants of family Sctiaminae. It has also been recorded on Zingiber sp. and on grasses.


Udea ferrugalis, the rusty dot pearl, is a moth of the family Crambidae. The species was first described by Jacob Hübner in 1796.


This species can be found in central and southern Europe, Asia Minor, Africa, India and Japan.


The wingspan is 18–22 mm. The forewings of these small moths have yellow, brown or ferruginous ground colour and prominent indistinct dark brown or blackish markings towards the edge. Hindwings are brownish grey. Legs are whitish. Caterpillars can reach a length of 10–15 millimetres (0.39–0.59 in). They are greenish with yellowish head.


These moths are bivoltine or trivoltine. The moth flies through the year, but mainly in the autumn, depending on location. The larvae feed on various herbaceous plants, such as Stachys, Arctium, Lycopus, Mentha, Eupatorium cannabinum and Fragaria vesca. They overwinter in the soil as a chrysalis. This species is sometimes considered a pest, as the larvae attack various crop plants.


Udea rubigalis, the celery leaftier or greenhouse leaftier, is a member of the family Crambidae. It is found across the Americas. The species was first described by Achille Guenée in 1854.
The larvae are polyphagous and feed on a wide variety of plants from different plant families. Preferred host plants are:
Calendula officinalis (Asteraceae)
Chrysanthemum × morifolium and Chrysanthemum frutescens (Asteraceae)
Senecio cruentus (Asteraceae)
Dianthus caryophyllus (Caryophyllaceae)
Lathyrus odoratus (Fabaceae)
Pelargonium hortorum (Geraniaceae)
Antirrhinum species (Plantaginaceae)
Rosa species (Rosaceae)
Viola tricolor (Violaceae)
The larvae have also been recorded to be less injuriously feeding on:
Justicia furcata (Acanthaceae)
Ruellia amoena (Acanthaceae)
Ageratum houstonianum (Asteraceae)
Callistephus chinensis (Asteraceae)
Cheiranthus sp. (Brassicaceae)
Cnicus benedictus (Asteraceae)
Dahlia rosea (Asteraceae)
Matricaria parthenoides (Asteraceae)
Senecio mikanioides (Asteraceae)
Tagetes species (Asteraceae)
Impatiens walleriana (Balsaminaceae)
Begonia species (Begoniaceae)
Heliotropium peruvianum (Boraginaceae)
Lobelia erinus (Campanulaceae)
Canna indica (Cannaceae)
Tradescantia fluminensis (Commelinaceae)
Ipomoea aculeata (Convolvulaceae)
Azalea species (Ericaceae)
Cytisus canariensis (Fabaceae)
Swainsona galegifolia (Fabaceae)
Kohleria inaequalis var. ocellata (Gesneriaceae)
Deutzia gracilis (Hydrangeaceae)
Coleus blumei (Lamiaceae)
Nepeta hederacea (Lamiaceae)
Salvia officinalis (Lamiaceae)
Abutilon species (Malvaceae)
Fuchsia speciosa (Onagraceae)
Passiflora caerulea (Passifloraceae)
Linaria cymbalaria (Plantaginaceae)
Veronica species (Plantaginaceae)
Plumbago capensis (Plumbaginaceae)
Cyclamen persicum (Primulaceae)
Primula species (Primulaceae)
Anemone japonica (Ranunculaceae)
Petunia hybrida (Solanaceae)
Tropaeolum species (Tropaeolaceae)
Lantana camara (Verbenaceae)


Ulex europaeus, the gorse, common gorse, furze or  whin, is a species of flowering plant in the family  Fabaceae, native to the British Isles and Western Europe.


Growing to 2–3 metres (7–10 ft) tall, it is an evergreen shrub. The young stems are green, with the shoots and leaves modified into green spines, 1–3 centimetres (0.39–1.18 in) long. Young seedlings produce normal leaves for the first few months; these are trifoliate, resembling a small clover leaf.
The solitary flowers are yellow, 1–2 centimetres (0.39–0.79 in) long, with the pea-flower structure typical of the Fabaceae; they are produced throughout the year, but mainly over a long period in spring. They are coconut-scented. The fruit is a legume (pod) 2 centimetres (0.79 in) long, dark purplish-brown, partly enclosed by the pale brown remnants of the flower; the pod contains 2–3 small blackish, shiny, hard seeds, which are ejected when the pod splits open in hot weather. Seeds remain viable for 30 years.
Like many species of gorse, it is often a fire-climax plant, which readily catches fire but re-grows from the roots after the fire; the seeds are also adapted to germinate after slight scorching by fire. It has a tap root, lateral and adventitious roots. An extremely tough and hardy plant, it survives temperatures down to −20 °C (−4 °F).  It can live for about thirty years.


The species has been introduced to other areas of Europe, and also to the Americas, New Zealand, South Africa, and Australia,  where it is often considered a weed and is a serious problem invasive species in some areas (notably the western United States, Chile and New Zealand). It was introduced to New Zealand from Scotland as a type of hedge, but became a major blight to farmers as the climate suited its growth better than its native habitat and many of its natural predators were absent.
Common gorse is also an invasive species in the montane grasslands of Horton Plains National Park in Sri Lanka. It outcompetes native, endemic species and is a fire hazard.
Biological pest control is used on this plant in many areas. The gorse spider mite (Tetranychus lintearius) and the gorse seed weevil (Exapion ulicis) reduce the spread of the plant.


This plant is used for hedging, boundary definition and groundcover in suitably sunny, open locations. Cultivars include 'Strictus' (Irish gorse), a dwarf form, and the double-flowered, non-fruiting 'Flore Pleno', which has gained the Royal Horticultural Society's Award of Garden Merit.


Bruised gorse was used in some areas for feeding to horses and other livestock.
Lectin extracted from seeds of this species binds to, is remarkably specific for, and is the standard method for identification of H substance (absent in the hh antigen system) on human red blood cells.  The vast majority of humans express H substance, which is the basis for the ABO blood group system, but a few rare individuals ("Bombay phenotype") do not—and a chemical isolated from Ulex europaeus is used to identify these individuals. This lectin is also used as a marker for human vascular endothelial cells, and as a tool for their isolation for in-vitro culture.
Like other legumes, it fixes nitrogen into the soil.


Ulmus americana, generally known as the American elm or, less commonly, as the white elm or water elm, is a species of elm native to eastern North America, naturally occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can withstand winter temperatures as low as −42 °C (−44 °F). Trees in areas unaffected by Dutch elm disease (DED) can live for several hundred years. A prime example of the species was the Sauble Elm, which grew beside the banks of the Sauble River in Ontario, Canada, to a height of 43 m (140 ft), with a d.b.h of 196 cm (6.43 ft) before succumbing to DED; when it was felled in 1968, a tree-ring count established that it had germinated in 1701.
For over 80 years, U. americana had been identified as a tetraploid, i.e. having double the usual number of chromosomes, making it unique within the genus. However, a study published in 2011 by the Agricultural Research Service of the USDA revealed that about 20% of wild American elms are diploid and may even constitute another species. Moreover, several triploid trees known only in cultivation, such as 'Jefferson', are possessed of a high degree of resistance to DED, which ravaged American elms in the 20th century. This suggests that the diploid parent trees, which have markedly smaller cells than the tetraploid, may too be highly resistant to the disease.


Ulmus americana was first described and named by Carl Linnaeus in his Species Plantarum, published in 1753. No subspecies or varieties are currently recognized within the species.


The American elm is a deciduous hermaphroditic tree which, before the introduction of DED, commonly grew to more than 100 feet (30 m) tall with a trunk whose diameter at breast height was more than 4 feet (1.2 m), supporting a high, spreading umbrella-like canopy. The leaves are alternate, 7–20 cm long, with double-serrate margins and an oblique base. The perfect flowers are small, purple-brown and, being wind-pollinated, apetalous. The flowers are also protogynous, the female parts maturing before the male, thus reducing, but not eliminating, self-fertilization, and emerge in early spring before the leaves. The fruit is a flat samara 2 cm long by 1.5 cm broad, with a circular papery wing surrounding the single 4–5 mm seed. As in the closely related European White Elm Ulmus laevis, the flowers and seeds are borne on 1–3 cm long stems. American Elm is wholly insensitive to daylight length (photoperiod), and will continue to grow well into autumn until injured by frost. Ploidy is 2n = 56, or more rarely, 2n = 28.


The American elm is highly susceptible to DED and elm yellows. In North America, there are three species of elm bark beetles: one native, Hylurgopinus rufipes ("native elm bark beetle"); and two invasive, Scolytus multistriatus ("smaller European elm bark beetle") and Scolytus schevyrewi ("banded elm bark beetle"). Although intensive feeding by elm bark beetles can kill weakened trees, their main impact is as vectors of DED.
American elm is also moderately preferred for feeding and reproduction by the adult elm leaf beetle Xanthogaleruca luteola and highly preferred for feeding by the Japanese beetle Popillia japonica in the United States.
U. americana is also the most susceptible of all the elms to verticillium wilt, whose external symptoms closely mimic those of DED. However, the condition is far less serious, and afflicted trees should recover the following year.


Dutch elm disease (DED) is a fungal disease that has ravaged the American elm, causing catastrophic die-offs in cities across the range. It has been estimated that only approximately 1 in 100,000 American elm trees is DED-tolerant, most known survivors simply having escaped exposure to the disease. However, in some areas still not infested by DED, the American elm continues to thrive, notably in Florida, Alberta and British Columbia. There is a notable grove of old American elm trees in Manhattan's Central Park. The trees there were apparently spared because of the grove's isolation in such an intensely urban setting.
The American elm is particularly susceptible to disease because the period of infection often coincides with the period, approximately 30 days, of rapid terminal growth when new springwood vessels are fully functional. Spores introduced outside of this period remain largely static within the xylem and are thus relatively ineffective.
The American elm's biology in some ways has helped to spare it from obliteration by DED, in contrast to what happened to the American chestnut with the chestnut blight. The elm's seeds are largely wind-dispersed, and the tree grows quickly and begins bearing seeds at a young age. It grows well along roads or railroad tracks, and in abandoned lots and other disturbed areas, where it is highly tolerant of most stress factors. Elms have been able to survive and to reproduce in areas where the disease had eliminated old trees, although most of these young elms eventually succumb to the disease at a relatively young age. There is some reason to hope that these elms will preserve the genetic diversity of the original population, and that they eventually will hybridize with DED-resistant varieties that have been developed or that occur naturally. After 20 years of research, American scientists first developed DED-resistant strains of elms in the late 1990s.
Elms in forest and other natural areas have been less affected by DED than trees in urban environments due to lower environmental stress from pollution and soil compaction and due to occurring in smaller, more isolated populations.
Fungicidal injections can be administered to valuable American elms, to prevent infection. Such injections generally are effective as a preventive measure for up to three years when performed before any symptoms have appeared, but may be ineffective once the disease is evident.


In the 19th and early 20th century, American elm was a common street and park tree owing to its tolerance of urban conditions, rapid growth, and graceful form. This however led to extreme overplanting of the species, especially to form living archways over streets, which ultimately produced an unhealthy monoculture of elms that had no resistance to disease and pests. Elms do not naturally form pure stands and trees used in landscaping were grown from a handful of cultivars, causing extremely low genetic diversity. These trees' rapid growth and longevity, leading to great size within decades, also favored its horticultural use before the advent of DED. Ohio botanist William B. Werthner, discussing the contrast between open-grown and forest-grown American elms, noted that:
In the open, with an abundance of air and light, the main trunk divides into several leading branches which leave the trunk at a sharp angle and continue to grow upward, gradually diverging, dividing and subdividing into long, flexible branchlets whose ends, at last, float lightly in the air, giving the tree a round, somewhat flattened top of beautifully regular proportions and characteristically fine twiggery.
It is this distinctive growth form that is so valued in the open-grown American elms of street plantings, lawns, and parks; along most narrower streets, elms planted on opposite sides arch and blend together into a leafy canopy over the pavement. However, elms can assume many different sizes and forms depending on the location and climate zone. The classic vase-shaped elm was mainly the result of selective breeding of a few cultivars and is much less likely to occur in the wild.


American elms have been planted in North America beyond its natural range as far north as central Alberta. It also survives low desert heat at Phoenix, Arizona.
Introductions across the Atlantic rarely prospered, even before the outbreak of DED. Introduced to the UK by James Gordon in 1752, the American elm was noted to be far more susceptible to insect foliage damage than native elms. The tree was propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire from 1945, with 450 sold in the period 1962 to 1977 when production ceased with the advent of the more virulent form of Dutch elm disease. Introduced to Australasia, the tree was listed by Australian nurseries in the early 20th century. It is known to have been planted along the Avenue of Honour at Ballarat, Victoria and the Avenue of Honour in Bacchus Marsh, Victoria. In addition, a heritage-listed planting of American elms can be found along Grant Crescent in Griffith, Australian Capital Territory. American Elms are only rarely found in New Zealand.


Mary Eleanor Wilkins Freeman, in her 1903 book of short stories, Six Trees, wrote of the American elm:
There was not in the whole countryside another tree which could compare with him. He was matchless. Never a stranger passed the elm but stopped, and stared, and said or thought something about it. Even dull rustics looked, and had a momentary lapse from vacuity.


Numerous cultivars have been raised, originally for their aesthetic merit but more recently for their resistance to Dutch elm disease The total number of named cultivars is circa 45, at least 18 of which have probably been lost to cultivation as a consequence of DED or other factors:

American Liberty
Ascendens
Augustine
Aurea
Beaverlodge
Beebe's Weeping
Brandon
Burgoyne
College
Columnaris
Creole Queen
Deadfree
Delaware
Exhibition
Fiorei
Flicks Spreader
Folia Aurea Variegata
Hines
Incisa
Independence
Iowa State
Jackson
Jefferson
JFS-Prince II = Colonial Spirit
Kimley
Klehmii
L'Assomption
Lake City
Lewis & Clark = Prairie Expedition
Littleford
Maine
Markham
Miller Park
Minneapolis Park
Moline
Morden
New Harmony
Nigricans
Patmore
Pendula
Penn Treaty
Princeton
Pyramidata
Queen City
Sheyenne
Skinner Upright
St. Croix
Star
Valley Forge
Variegata
Vase
Washington
 and others.
The disease-resistant selections made available to commerce to date include 'Valley Forge', 'New Harmony', 'Princeton', 'Jefferson', 'Lewis & Clark', 'Miller Park', 'St. Croix', and a set of six different clones collectively known as 'American Liberty'. The United States National Arboretum released 'Valley Forge' and 'New Harmony' in late 1995, after screening tests performed in 1992–1993 showed both had unusually high levels of resistance to DED. 'Valley Forge' performed especially well in these tests.
'Princeton' has been in occasional cultivation since the 1920s. 'Princeton' gained renewed attention after its performance in the 1992—1993 screening tests showed that it also had a high degree of disease resistance. A later test performed in 2002–2003 confirmed the disease resistance of 'Princeton', 'Valley Forge' and 'New Harmony', as well as that of 'Jefferson'.  Thus far, plantings of these four varieties generally appear to be successful.
In 2005, approximately 90 'Princeton' elms were planted along Pennsylvania Avenue in front of the White House in Washington, D.C. The trees, whose maintenance the National Park Service (NPS) manages, remain healthy and are thriving. However, it has  been noted that U. americana cultivars are not recommended for more than singular plantings as they have unresolved DED and elm yellows concerns.
It has also been noted that monoculture plantings of U. americana cultivars, such as those along Pennsylvania Avenue, have disproportionate vulnerabilities to disease. Further, long-term studies of 'Princeton' in Europe and the United States have suggested that the cultivar's resistance to DED may be limited (see Pests and diseases of 'Princeton').
The National Elm Trial evaluated 19 elm cultivars commercially available in the United States in scientific plantings throughout the nation to assess and compare the strengths and weaknesses of each. The trial, which started in 2005, lasted for ten years. Based on the  trial's final ratings, the preferred cultivars of U. americana are 'New Harmony' and 'Princeton'.
'Jefferson' was released to wholesale nurseries in 2004 and is becoming increasingly available for planting. However, 'Jefferson' has not been widely tested beyond Washington, D.C. The National Elm Trial provided no data on ‘Jefferson’ because an error in tree identification had occurred earlier in the nursery trade. The error may still be causing nurseries to sell 'Princeton' elms that are mislabeled as 'Jefferson', although one can distinguish between the two cultivars as the trees mature.
In 2007, the 'Elm Recovery Project' from the University of Guelph in Ontario, Canada, reported that cuttings from healthy surviving old elms surveyed across Ontario had been grown to produce a bank of resistant trees, isolated for selective breeding of highly resistant cultivars.
In 1993, Mariam B. Sticklen and James L. Sherald reported the results of NPS-funded experiments conducted at Michigan State University in East Lansing that were designed to apply genetic engineering techniques to the development of DED-resistant strains of American elm trees. In 2007, AE Newhouse and F Schrodt of the State University of New York College of Environmental Science and Forestry in Syracuse reported that young transgenic American elm trees had shown reduced DED symptoms and normal mycorrhizal colonization.


Ulmus 'Rebella' (U. americana × U. parvifolia)
Thousands of attempts to cross the American elm with the Siberian elm U. pumila failed. Attempts at the Arnold Arboretum using ten other American, European and Asiatic species also ended in failure, attributed to the differences in ploidy and operational dichogamy, although the ploidy factor has been discounted by other authorities.
Success was eventually achieved with the autumn-flowering Chinese elm Ulmus parvifolia by the late Prof. Eugene Smalley towards the end of his career at the University of Wisconsin–Madison after he overcame the problem of keeping Chinese elm pollen alive until spring. Only one of the hybrid clones was commercially released, as 'Rebella' in 2011 by the German nursery Eisele GmbH; the clone is not available in the United States.
Other artificial hybridizations with American elm are rare, and now regarded with suspicion. Two such alleged successes by the nursery trade were 'Hamburg', and 'Kansas Hybrid', both with Siberian elm Ulmus pumila. However, given the repeated failure with the two species by research institutions, it is now believed that the "American elm" in question was more likely to have been the red elm, Ulmus rubra.


The American elm's wood is coarse, hard, and tough, with interlacing, contorted fibers that make it difficult to split or chop, and cause it to warp after sawing. Accordingly, the wood originally had few uses, save for making hubs for wagon wheels. Later, with the advent of mechanical sawing, American elm wood was used for barrel staves, trunk-slats, and hoop-poles, and subsequently became fundamental to the manufacture of wooden automobile bodies, with the intricate fibers holding screws unusually well.


Young twigs and branchlets of the American elm have tough, fibrous bark that has been used as a tying and binding material, even for rope swings for children, and also for making whips.


A number of mostly small to medium-sized American elms now survive in woodlands, suburban areas, and occasionally cities, where the survivors have often been relatively isolated from other elms and thus spared a severe exposure to the fungus. For example, in Central Park and Tompkins Square Park in New York City, stands of several large elms originally planted by Frederick Law Olmsted survive because of their isolation from neighboring areas in New York where there had been heavy mortality. The Olmsted-designed park system in Buffalo, NY did not fare as well.
A row of mature American elms lines Central Park along the entire length of Fifth Avenue from 59th to 110th Streets. In Akron, Ohio there is a very old elm tree that has not been infected. In historical areas of Philadelphia, Pennsylvania, there are also a few mature American elms still standing — notably in Independence Square and the Quadrangle at the University of Pennsylvania, and also at the nearby campuses of Haverford College, Swarthmore College, and Pennsylvania State University, believed to be the largest remaining stand in the country.
There are several large American Elm trees in western Massachusetts. A large specimen, which stands on Summer Street in the Berkshire County town of Lanesborough, Massachusetts, has been kept alive by antifungal treatments. Rutgers University has preserved 55 mature elms on and in the vicinity of Voorhees Mall on the College Avenue Campus in New Brunswick, New Jersey in addition to seven disease-resistant trees that have been planted in this area of the campus in recent years.
The largest surviving urban forest of American elms in North America is believed to be in the city of Winnipeg, Manitoba, Canada, where close to 200,000 elms remain. The city of Winnipeg spends $3M annually to aggressively combat the disease utilizing Dursban Turf and the Dutch Trig vaccine, losing 1500–4000 trees per year.
Governmental agencies, educational institutions or other organizations in most of the states that are within the United States maintain lists of champion or big trees that describe the locations and characteristics of those states' largest American elm trees (see List of state champion American elm trees). The current United States national champion American elm tree is located in Iberville Parish, Louisiana. When measured in 2010, the tree had a trunk circumference of 324 inches (820 cm), a height of 111 feet (34 m) and an average crown spread of 79 feet (24 m).
The current Tree Register of the British Isles (TROBI) champion grows in Avondale Forest near Rathdrum, County Wicklow, Ireland. The tree had a height of 22.5 metres (74 ft) and a diameter at breast height of 98 centimetres (39 in) (circumference of 308 centimetres (121 in)) when measured in 2000. The tree replaced on the Register a larger champion located in Woodvale Cemetery in Sussex, England, which in 1988 had a height of 27 metres (89 ft) and a diameter of 115 centimetres (45 in) (circumference of 361 centimetres (142 in)).
Other large or otherwise significant American elm trees have included:


The Logan Elm that stood near Circleville, Ohio, was one of the largest American elms in the world. The 65-foot-tall (20 m) tree had a trunk circumference of 24 feet (7.3 m) and a crown spread of 180 feet (55 m). Weakened by DED, the tree died in 1964 from storm damage. The Logan Elm State Memorial commemorates the site and preserves various associated markers and monuments. According to tradition, Chief Logan of the Mingo tribe delivered a passionate speech at a peace-treaty meeting under this elm in 1774.


The Glencorradale Elm on Prince Edward Island, Canada, is a surviving wild elm believed to be several hundred years old.


New York City's Central Park is home to approximately 1,200 American elms. The oldest of these elms were planted during the 1860s by Frederick Law Olmsted, making them among the oldest stands of American elms in the world. The trees are particularly noteworthy along the Mall and Literary Walk, where four lines of American elms stretch over the walkway forming a cathedral-like covering. A part of New York City's urban ecology, the elms improve air and water quality, reduce erosion and flooding, and decrease air temperatures during warm days.
While the stand is still vulnerable to DED, in the 1980s the Central Park Conservancy undertook aggressive countermeasures such as heavy pruning and removal of extensively diseased trees. These efforts have largely been successful in saving the majority of the trees, although several are still lost each year. Younger American elms that have been planted in Central Park since the outbreak are of the DED-resistant 'Princeton' and 'Valley Forge' cultivars.


Several rows of American elm trees that the National Park Service first planted during the 1930s line much of the 1.9 miles (3.0 km) length of the National Mall in Washington, D.C. DED first appeared on the trees during the 1950s and reached a peak in the 1970s. The NPS used a number of methods to control the epidemic, including sanitation, pruning, injecting trees with fungicide and replanting with DED-resistant cultivars. The NPS combated the disease's local insect vector, the smaller European elm bark beetle (Scolytus multistriatus), by trapping and by spraying with insecticides. As a result, the population of American elms planted on the Mall and its surrounding areas has remained intact for more than 80 years.


The nobility and arching grace of the American Elm in its heyday, on farms, in villages, in towns and on campuses, were celebrated in the books of photographs of Wallace Nutting (Massachusetts Beautiful, N.Y. 1923, and other volumes in the series) and of Samuel Chamberlain (The New England Image, New York, 1962). Frederick Childe Hassam is notable among painters who have depicted American Elm.


North America
Arnold Arboretum, US. Acc. nos. 250-53 (cult. material), 412-86 wild collected in the United States.
Bernheim Arboretum and Research Forest, Clermont, Kentucky. No details available.
Denver Botanic Gardens, US. One specimen, no details.
Holden Arboretum, US. Acc. nos. 2005-17, 65-632, 80-663, all of unrecorded provenance.
Longwood Gardens, US. Acc. nos. 1997-0074, L-0352, sources unrecorded.
Missouri Botanical Garden, US. Acc. nos. 1969-6172, 1986-0206, 1986-0207, 1986-0208.
New York Botanical Garden, US. Acc. nos. 877/97, 944/96, 1854/99, 2111/99, 06791, all unrecorded provenance.
Phipps Conservatory & Botanical Gardens, US. Acc. nos. 00/1265, 99/0660.
Scott Arboretum, US. Acc. no. S000339, no other details available.
U S National Arboretum, Washington, D.C., US. Acc. nos. 64254, 64255, 64256, 66355, 66426, 68988, 69304, 66341.
Europe
Brighton & Hove City Council, UK. NCCPG elm collection.
Dubrava Arboretum, Lithuania. No accession details available.
Grange Farm Arboretum, Sutton St James, Spalding, Lincolnshire, UK. Acc. no. not known.
Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18087,88,89,90,91,92.
Linnaean Gardens of Uppsala, Sweden. Acc. nos. 1976-2713,0000-2170
Strona Arboretum, University of Life Sciences, Warsaw, Poland. No accession details available.
Royal Botanic Garden Edinburgh, UK. Acc. no. 19901741, Ulmus americana L., wild collected in Canada; Acc. no. 19802124, Ulmus americana L.× pumila L. var. arborea, cultivated material
Tallinn Botanic Garden, Estonia. No accession details available.
Thenford House arboretum, Northamptonshire, UK. No accession details available.
University of Copenhagen, Botanic Garden, Denmark. Acc. no. P1971-5201, wild collected in the US
Wakehurst Place Garden, Wakehurst Place, UK. Acc. nos. 1994-67, 1994-68, 1991-1163.A.
Australasia
Eastwoodhill Arboretum, Gisborne, New Zealand. 11 trees, accession details not known.


Ulmus glabra, the wych elm or Scots elm, has the widest range of the European elm species, from Ireland eastwards to the Urals, and from the Arctic Circle south to the mountains of the Peloponnese in Greece; it is also found in Iran. A large deciduous tree, it is essentially a montane species, growing at elevations up to 1,500 m (4,900 ft), preferring sites with moist soils and high humidity. The tree can form pure forests in Scandinavia and occurs as far north as latitude 67°N at Beiarn in Norway. It has been successfully  introduced as far north as Tromsø, Norway and Alta, Norway (70°N). It has also been successfully introduced to Narsarsuaq, near the southern tip of Greenland (61°N).
The tree was by far the most common elm in the north and west of the British Isles and is now acknowledged as the only indisputably British native elm species. Owing to its former abundance in Scotland, the tree is occasionally known as the Scotch or Scots elm; Loch Lomond is said to be a corruption of the Gaelic Lac Leaman interpreted by some as 'Lake of the Elms', 'leaman' being the plural form of leam or lem, 'elm'.
Closely related species, such as Bergmann's elm U. bergmanniana and Manchurian elm U. laciniata, native to northeast Asia, were once sometimes included in U. glabra; another close relative is the Himalayan or Kashmir elm U. wallichiana. Conversely, Ulmus elliptica from the Caucasus, considered a species by some authorities, is often listed as a regional form of Ulmus glabra.


The word "wych" (also spelled "witch") comes from the Old English wice, meaning pliant or supple, which also gives definition to wicker and weak. Jacob George Strutt's 1822 book, Sylva Britannica attests that the Wych Elm was sometimes referred to as the "Wych Hazel". (not to be confused with Hamamelis wych hazels).


Some botanists, notably Lindquist (1931), have proposed two subspecies:
U. glabra subsp. glabra in the south of the species' range: broad leaves with short tapering base and acute lobes; trees often with a short, forked trunk and a low, broad crown;
U. glabra subsp. montana (Stokes) Lindqvist in the north of the species' range (northern Britain, Scandinavia): leaves narrower, with a long tapering base and without acute lobes; trees commonly with a long single trunk and a tall, narrow crown.
Much overlap is seen between populations with these characters, and the distinction may owe to environmental influence, rather than genetic variation; the subspecies are not accepted by Flora Europaea.


The type sometimes reaches heights of 40 m (130 ft), typically with a broad crown where open-grown, supported by a short bole up to 2 m (6.6 ft) diameter at breast height (DBH). Normally, root suckers are not seen; natural reproduction is by seed alone. The tree is notable for its very tough, supple young shoots, which are always without the corky ridges or 'wings' characteristic of many elms. The alternate leaves are deciduous, 6–17 cm long by 3–12 cm broad, usually obovate with an asymmetric base, the lobe often completely covering the short (<5 mm) petiole; the upper surface is rough. Leaves on juvenile or shade-grown shoots sometimes have three or more lobes near the apex. The perfect hermaphrodite flowers appear before the leaves in early spring, produced in clusters of 10–20; they are 4 mm across on 10 mm long stems, and being wind-pollinated, are apetalous. The fruit is a winged samara 20 mm long and 15 mm broad, with a single, round, 6 mm seed in the centre, maturing in late spring.


While the species is highly susceptible to Dutch elm disease, it is less favoured as a host by the elm bark beetles, which act as vectors. Research in Spain has indicated the presence of a triterpene, alnulin, rendering the tree bark less attractive to the beetle than the field elm, though at 87 μg/g dried bark, its concentration is not as effective as in Ulmus laevis (200 μg/g). Moreover, once the tree is dying, its bark is quickly colonized by the fungus Phoma, which radically reduces the amount of bark available for the beetle to breed on. In European trials, clones of apparently resistant trees were inoculated with the pathogen, causing 85 – 100% wilting, resulting in 68% mortality by the following year. DNA analysis by Cemagref (now Irstea) in France has determined the genetic diversity within the species is very limited, making the chances of a resistant tree evolving rather remote.
Still, a 300-year-old example growing in Grenzhammer, Ilmenau has been scientifically proven to be resistant to Dutch elm disease
The Swedish Forest Tree Breeding Association at Källstorp produced triploid and tetraploid forms of the tree, but these proved no more resistant to Dutch elm disease than the normal diploid form.
In trials conducted in Italy, the tree was found to have a slight to moderate susceptibility to elm yellows, and a high susceptibility to the elm leaf beetle Xanthogaleruca luteola.


The wych elm is moderately shade-tolerant, but requires deep, rich soils as typically found along river valleys. The species is intolerant of acid soils and flooding, as it is of prolonged drought. Although rarely used as a street tree owing to its shape, it can be surprisingly tolerant of urban air pollution, constricted growing conditions, and severe pollarding.
As wych elm does not sucker from the roots, and any seedlings are often consumed by uncontrolled deer populations, regeneration is very restricted, limited to sprouts from the stumps of young trees. The resultant decline has been extreme, and the wych elm is now uncommon over much of its former range. It is best propagated from seed or by layering stooled stock plants, although softwood cuttings taken in early June will root fairly reliably under mist.
Wych elm was widely planted in Edinburgh in the 19th century as a park and avenue tree, and despite losses, it remains abundant there, regenerating through seedlings. It was introduced to New England in the 18th century, to Canada (as U. montana at the Dominion Arboretum, Ottawa)  and Australia in the 19th century.


Wych elm wood is prized by craftsmen for its colouring, its crazy grain, its 'partridge-breast' or 'catspaw' markings, and when worked, its occasional iridescent greenish sheen or 'bloom'. The bosses on old trees produce the characteristic fissures and markings of 'burr elm' wood. Bosses fringed with shoots are burrs, whereas unfringed bosses are burls.


In 18th century France, the inner bark of Ulmus glabra, orme pyramidale, had a brief reputation as a panacea;
"it was taken as a powder, as an extract, as an elixir, even in baths. It was good for the nerves, the chest, the stomach — what can I say? — it was a true panacea." It was this so-called "pyramidal elm bark" about which Michel-Philippe Bouvart famously quipped "Take it, Madame... and hurry up while it [still] cures." It still appeared in a pharmacopeia of 1893.


E. M. Forster cites a particular wych elm, one that grew at his childhood home of Rooks Nest, Stevenage, Hertfordshire, 16 times in his novel Howards End.  This tree overhangs the house of the title and is said to have a "...girth that a dozen men could not have spanned..."  Forster describes the tree as "...a comrade, bending over the house, strength and adventure in its roots."  The wych elm of the novel had pigs' teeth embedded in the trunk by country people long ago and it was said that chewing some of the bark could cure toothache.  In keeping with the novel's epigraph, "Only connect...", the wych elm may be seen by some as a symbol of the connection of humans to the earth.  Margaret Schlegel, the novel's protagonist, fears that any "....westerly gale might blow the wych elm down and bring the end of all things..."  The tree is changed to a chestnut in the 1991 film adaptation of Howards End.
The UK Champion listed in the Tree Register of the British Isles is at Brahan in the Scottish Highlands; it has a girth of 703 cm (2.23 m DBH) and a height of 24 m. Possibly the oldest specimen in England was found in 2018 in a field north of Hopton Castle in Shropshire. Coppiced long ago, its bole girth measured 6.3  m in 2018. The oldest specimen in Edinburgh is believed to be the tree (girth 5.2 m) in the former grounds of Duddingston House, now Duddingston Golf Course. Other notable specimens in Edinburgh are to be found in Learmonth Gardens and The Meadows.
In Europe, a large tree planted in 1620 grows at Bergemolo, 5 km south of Demonte in Piedmont, Italy (bole-girth 6.2 m, 2.0 m  DBH, height 26 m., 2008). Other ancient specimens grow at Styria, in Austria, and at Grenzhammer, Germany (see Gallery). In 1998, over 700 healthy, mature trees were discovered on the upper slopes of Mount Šimonka in Slovakia, but they are believed to have survived courtesy of their isolation from disease-carrying beetles rather than any innate resistance; 50 clones of these trees were presented to the Prince of Wales for planting at his Highgrove Estate, and at Clapham, Yorkshire.


About 40 cultivars have been raised, although at least 30 are now probably lost to cultivation as a consequence of Dutch elm disease and/or other factors:
Albo-Variegata
Australis
Camperdownii
Cebennensis
Concavaefolia
Cornuta
Corylifolia Purpurea
Corylifolia
Dovaei
Fastigiata Macrophylla
Fastigiata Stricta
Fastigiata Variegata
Firma
Flava
Gigantea
Gittisham
Grandidentata
Holgeri
Horizontalis
Insularis
Latifolia
Latifolia Aurea
Latifolia Aureo-Variegata
Latifolia Nigricans
Luteo Variegata
Lutescens
Macrophylla
Maculata
Minor
Nana
Nitida
Nigra
Oblongata
Pendula Macrophylla
Pendula Variegata
Pyrenaica
Spectabilis
Superba
Tomentosa
NB: 'Exoniensis', Exeter Elm, has traditionally been classified as a form of U. glabra, but its identity is now a matter of contention.


U. glabra hybridises naturally with U. minor, producing elms of the Ulmus × hollandica group, from which have arisen a number of cultivars:
Alba
Angustifolia
Balder
Belgica
Blandford
Canadian Giant
Cicestria
Cinerea
Commelin
Dampieri
Dauvessei
Daveyi
Dumont
Elegantissima
Eleganto-Variegata
Etrusca
Fastigiata
Fjerrestad
Folia Rhomboidea
Freja
Fulva
Gaujardii
Groeneveld
Haarlemensis
Klemmer
Loke
Macrophylla Aurea
Major
Microphylla
Modiolina
Muscaviensis
Nottingham
Odin
Pioneer
Pitteurs
Serpentina
Smithii
Superba
Tricolor
Tyr
Vegeta
Viminalis
Viscosa
Wentworthii Pendula
Wredei
Ypreau
However, hybrids of U. glabra and U. pumila, the Siberian elm, have not been observed in the field and only achieved in the laboratory, though the ranges of the two species, the latter introduced by man, overlap in parts of Southern Europe, notably Spain. A crossing in Russia of U. glabra and U. pumila produced the hybrid named Ulmus × arbuscula.
Hybrids with U. glabra in their ancestry have featured strongly in recent artificial hybridization experiments in Europe, notably at Wageningen in the Netherlands, and a number of hybrid cultivars have been commercially released since 1960. The earlier trees were raised in response to the initial Dutch elm disease pandemic that afflicted Europe after the First World War, and were to prove vulnerable to the much more virulent strain of the disease that arrived in the late 1960s. However, further research eventually produced several trees effectively immune to disease, which were released after 1989.
Arno, Clusius, Columella, Commelin, Den Haag, Dodoens, Groeneveld, Homestead, Lobel, Nanguen = Lutèce, Pioneer, Plinio, Regal, San Zanobi, Urban, Wanoux = Vada.


North America
Arnold Arboretum, US. Acc. no. 391–2001, wild collected in Georgia
Bartlett Tree Experts, US. Acc. nos. 1505, 5103, origin undisclosed
Dawes Arboretum , US. 6 trees, no acc. details available
Missouri Botanical Garden , US. Acc. nos. 1969–6164, 1986–0160
Morton Arboretum, US. Acc. nos. 591–54, 255–81, and by its synonym U. sukaczevii, acc. nos. 949–73, 181–76
Europe
[Held in nearly all arboreta]
Australasia
Eastwoodhill Arboretum , Gisborne, New Zealand. 8 trees, details not known.


Ulmus laevis Pall., variously known as the European white elm, fluttering elm, spreading elm, stately elm and, in the United States, the Russian elm, is a large deciduous tree native to Europe, from France northeast to southern Finland, east beyond the Urals into Kyrgyzstan and Kazakhstan, and southeast to Bulgaria and the Crimea; there are also disjunct populations in the Caucasus and Spain, the latter now considered a relict population rather than an introduction by man, and possibly the origin of the European population. U. laevis is rare in the UK, although its random distribution, together with the absence of any record of its introduction, has led at least one British authority to consider it native. NB: The epithet 'white' elm commonly used by British foresters alluded to the timber of the wych elm.
The species was first identified, as Ulmus laevis, by Pallas, in his Flora Rossica published in 1784. The tree is allogamous and is most closely related to the American elm U. americana.
Endemic to alluvial forest, U. laevis is rarely encountered at elevations above 400 m. Most commonly found along rivers such as the Volga and Danube, it is one of very few elms tolerant of prolonged waterlogged, anoxic ground conditions. The species is threatened by habitat destruction and disturbance in some countries, notably Spain. Flood control schemes are particularly harmful, as seed dispersion is reliant on floods, while abstraction from aquifers lowering ground water levels has compromised the development of the trees.
Although not possessed of an innate genetic resistance to Dutch elm disease, the species is rarely infected in western Europe.


Ulmus laevis is similar in stature to the wych elm, if rather less symmetric, with a looser, untidy, branch structure and less neatly rounded crown. The tree typically reaches a height and breadth of > 30 m, with a trunk < 2 m d.b.h. The extensive shallow root system ultimately forms distinctive high buttresses around the base of the trunk. The bark is smooth at first, then in early maturity breaks into thin grey scales, which separate with age into a network of grey-brown scales and reddish-brown underbark, and finally is deeply fissured in old age like other elms. The leaves are deciduous, alternate, simple ovate with a markedly asymmetric base, < 10 cm long and < 7 cm broad, comparatively thin, often almost papery in texture and very translucent, smooth above with a downy underside. Significantly, the leaf veins do not divide from the central vein to the leaf margin. The leaves are shed earlier in autumn than other species of European elm.
The tree is most reliably distinguished from other European elms by its long flower stems, averaging 20 mm. Moreover, the apetalous wind-pollinated flowers are distinctively cream-coloured, appearing before the leaves in early spring in clusters of 15-30; they are 3–4 mm across. The fruit is a winged samara < 15 mm long by 10 mm broad with a ciliate margin, the single round 5 mm seed maturing in late spring. The seeds have a generally high rate of germination, 45–60% for Serbian trees examined by Stilinović.
Although the species is protandrous, levels of self-pollination can be high  The tree can grow very rapidly; where planted in persistently moist soil, trunk width of 13-year-old trees increased by 4 cm per annum at breast height (d.b.h.). The species differs from its closest relative, the American elm, mainly in the irregular crown structure and frequent epicormic shoots, features which also give the tree a distinctive winter silhouette. The American elm also has less acute leaf buds, longer petioles, narrower leaves, and a deeper apical notch in the samara which reaches the seed.


Like other European elms, natural populations of the European white elm have little innate resistance to Dutch elm disease, although research by Irstea has isolated clones able to survive inoculation with the causal fungus, initially losing < 70% of their foliage, but regenerating strongly the following year. Moreover, the tree is not favoured by the vector bark beetles, which colonize it only when there are no other elm alternatives available, an uncommon situation in western Europe. Indeed, in a study of elm in Flanders, not one example of U. laevis was found to be afflicted by Dutch elm disease. Meanwhile in France, the IRSTEA clone F298L completely  recovered four years after natural infection.
Research in Spain has indicated that it is the presence of an antifeedant triterpene, alnulin, at a concentration of 200 μg/g {dried bark} which renders the tree unattractive to the beetles. Ergo: the tree's decline in western Europe has been chiefly owing to woodland clearance in river valleys, and river management systems eliminating flooding, not disease.
However, in 2020, it was noted by the Dutch forestry commission that many laevis in Zeeland were succumbing to Dutch elm disease,  likewise in Hampshire, England.
It was noted by Jouin at Metz, and a century later by Mittempergher and Santini in Italy, that U. laevis had a very low susceptibility to the elm leaf beetle Xanthogaleruca luteola. Research in Germany has established that the tree is also eschewed by the Zig Zag sawfly Aproceros leucopoda.
Elwes observed that trees planted at Ugbrooke in Devon were infested with Cacopsylla ulmi, which he had never found on any other elm in Britain, an affliction confirmed many years later by Richens, who discovered the specimens of U. laevis grown at Kew were the only elms in the Gardens afflicted by the louse, and the aphid Tinocallis platani.
The species has a slight to moderate susceptibility to elm yellows.


U. laevis is essentially a riparian tree, able to withstand over 100 days of continual flooding, although it is intolerant of saline conditions   Spanish trees were found to be calcifuge, preferring slightly acid, siliceous soils, and also drought-intolerant, their xylem vessels prone to drought-stress cavitation. In England, the tree failed to prosper in chalk stream valleys, where the soil was predominantly black peat, named 'Adventurers' for the Adventurers' Land SSSI in Cambridgeshire, owing to dehydration in summer. Trees planted in dry ground are notoriously short-lived.
U. laevis is comparatively weak-wooded, much more so than field elm Ulmus minor, and thus an inappropriate choice for exposed locations. In trials in southern England by Butterfly Conservation, young trees of <5 m height were badly damaged by wind gusts of 40 knots (75 km/h) in midsummer storms.
The species was never widely introduced to the United States, but is represented at several arboreta. Ulmus effusa, supplied by the Späth nursery of Berlin, was planted at the Dominion Arboretum, Ottawa, Canada, in 1896, as U. pedunculata. In the Far East, the tree has been planted in Xinjiang province and elsewhere in northern China; planting in Tongliao City is known to have been particularly successful. White elm is also known to have been introduced to Australia.
Since the beginning of the 21st century, the tree has enjoyed a small renaissance in England. A popular larval host plant of the white-letter hairstreak Satyrium w-album butterfly across Europe, the elm is now being planted by Butterfly Conservation and other groups to restore local populations decimated by the effects of Dutch elm disease on native or archaeophytic elms. The Cheshire Wildlife Trust, for example, planted numerous white elms on its reserves in the former Vale Royal district of the county.


U. laevis is probably not native to the United Kingdom despite its random occurrence in the countryside, although the date and circumstances of its introduction have not survived. The earliest published references to the tree (as U. effusa, citing Willdenow) were in Sibthorp's Flora Oxoniensis (1794), and (as U. effusa Willd. but without description) in Miller's posthumously revised Gardener's and Botanist's Dictionary (1807). The first specimen to be reported in cultivation, in 1838, was at Whiteknights Park, Reading, which featured an elm grove;  the tree measured 63 ft (19 m) in height, suggesting it had been planted at the end of the 18th century. However, the authenticity of the Whiteknights tree is a matter of contention; it flowered but did not set fertile seed, which suggested to Loudon that it might be U. campestris (U. minor 'Atinia'), or, on account of it not producing suckers, possibly U. montana (:U. glabra). Moreover, Whiteknights was supplied by the Lee and Kennedy nursery of Hammersmith, which is not known to have stocked U. laevis. A tree at Syon Park identified by Elwes & Henry as U. laevis was later considered by Bean as more closely resembling U. americana by dint of its symmetrical branch arching. The species was not reported from the wild until 1943, with the discovery of a tree in a Surrey hedgerow.
It is possible the tree's distribution was associated with Capability Brown (1716–1783), known to have favoured U. laevis, which he listed among his preferred "native" (sic) trees. This could explain the existence of the seven old specimens discovered by Elwes in 1908 on Mount Pleasant within Ugbrooke Park, Devon, designed by Brown in 1761. Ugbrooke is four miles from Mamhead Park, which had earlier been planted with numerous exotic trees, notably holm oak, collected by its owner, merchant Thomas Ball ( d. 1749) during his commercial travels in Europe. Ball's introductions were known to have been marketed by his head gardener William Lucombe, who in 1720 founded the first commercial nursery in the south-west at Exeter, though an account of trees growing at Mamhead by Pince (grandson of Lucombe) in 1835 makes no mention of U. laevis nor of any other elms. None of Lucombe's early catalogues are known to survive, and thus the introduction of U. laevis through south Devon cannot be confirmed. However, the tree does not feature in any of the surviving arboreta accessions lists, or catalogues of the larger, nationally famous, nurseries of the day, and its earliest-known mention in commerce remains in the south-west, in the catalogue of the Ford & Please nursery (as U. pedunculata) at Exeter circa 1836. James Main mentions the tree as 'a native of Hungary' and in 1838 only to be met in 'ornamental plantations', but by 1846 was 'becoming available in (UK) nurseries'.
U. laevis, obtained from the Späth nursery of Berlin as U. effusa, was planted in Kew Gardens (1895), in the Ryston Hall arboretum, Norfolk (1914), and, re-propagated, in Cambridge University Botanic Garden (1909). Evidently the tree did not gain in popularity, and was overlooked or ignored by most authors of popular guides to trees in Britain during the 20th century, notably Mabey in his Flora Britannica. The tree is also omitted from Keble-Martin's comprehensive Flora of Devon.
It is not known whether U. laevis was introduced to Scotland before the early 20th century. Two of the three specimens supplied by the Späth nursery, Berlin, to the Royal Botanic Garden Edinburgh in 1902 as U. effusa may survive in Edinburgh, as it was the practice of the garden to distribute trees about the city; the third specimen was in the garden itself. Other examples can be found in the city, notably in Fettes College grounds opposite Inverleith Allotments, and at the entrance to North Merchiston Cemetery. In Wales, two mature trees with numerous seedlings occur in a small wood at Rhydyfelin near Aberystwyth, while another grows at Llandegfan, Anglesey. In Ireland, the tree is represented by a line of four at the Old Rectory, Kells Road, Ardee, County Louth (22 m or 72 ft, girth 3 m or 9.8 ft, October 2009), and in the Channel Islands, by a clump near the well at La Seigneurie (Le Manoir), Sark.


The two largest known trees in Europe are at Gülitz in Germany (3.1 m d.b.h.), and at Komorów in Poland (2.96 m d.b.h. in 2011), known as the Witcher (tree). Other veterans survive at Casteau, Belgium (bole-girth 5.15 m), in Rahnsdorf near Berlin (bole-girth 4.5 m) and in Ritvala, Finland (bole-girth 4.49 m).
A lane of Ulmus laevis is found at Eibergen, Netherlands (see Gallery below), while a large, mature specimen is found within the Alhambra, Granada.
Ulmus laevis has very occasionally been planted as an ornamental tree in the UK, and even more randomly in countryside hedgerows. The UK Champion is at Ferry Farm, on the banks of the Tamar at Harewood, Cornwall (27 m high, 1.8 m d.b.h. in 1997).  Other examples are few and far between though sometimes of considerable age, surviving amid diseased native elm in Cornwall at Torpoint, and Pencalenick (21 m high, d.b.h. 1.75 m), and near Over Wallop in Hampshire (16 m high, d.b.h. 1.3 m 2016) The largest-known aggregation in England is the ring of 50 trees planted circa 1950 within a ring of common lime around a former ammunition dump on the elevated chalk of Salisbury Plain at Hexagon Wood, Larkhill, about 2 km (1.2 mi) north of Stonehenge.
In the United States, a tree of 31.4 m (103 ft) in height (2015) grows at 3331 NE Hancock Street in Portland, Oregon; its age is not known.


The timber of the white elm is of poor quality, the cross-grain causing problems when machined, and thus of little practical use, not even as firewood. The density of the timber is significantly lower than that of other European elms. However, owing to its rapid growth, tolerance of soil compaction, air pollution and de-icing salts, the tree has long been used for amenity planting in towns and along roadsides.


U. laevis is easily grown from seed sown on ordinary compost and kept well-watered. However,  viability can vary greatly from year to year, while the seed is remarkably short-lived. Germination should occur within one week even without heat, the best seedlings attaining as much as half a metre in their first year. Softwood cuttings taken in June is also a reliable method; the cuttings strike very quickly, well within a fortnight, rapidly producing a dense matrix of roots.


Several putative varieties have been identified. A variety celtidea from what is now the Ukraine was reported by Rogowicz in the middle of the 19th century, but no examples are known to survive. Another variety parvifolia has been reported from Serbia. 'Simplicidens' is a very rare variety, the only example known to survive is at the National Botanic Garden of Latvia in Salaspils.


Compared with the other European species of elm, U. laevis has received scant horticultural attention, there being only eight recorded cultivars:
Aureovariegata
Colorans
Hardingen
Helena
Ornata
Pendula
Punctata
Urticifolia
In Russia other ornamental forms are recognized: f. argentovariegata, f. rubra, and f. tiliifolia. A pyramidal form was reported in 1888 from the Fredericksfelde cemetery in Berlin by Bolle. A line of similar monopodial trees grows (2019) on the island in the Lot at Entraygues, France.


U. laevis does not hybridize naturally, in common with the American elm (U. americana) to which it is closely related. However, in experiments at the Arnold Arboretum, it was successfully crossed with U. thomasii and U. pumila; no such crosses have ever been released to commerce.


Arnold Arboretum, US. Acc. nos. 17910, 637-79, 6951, 753-80.
Brenton Arboretum, Dallas Center, Iowa, US. No details available.
Brooklyn Botanic Garden, New York City, US. Acc. no. X02589.
Dominion Arboretum, Canada. No details available
Longwood Gardens, US. Acc. nos. 1964-0568, 1964-1119.
Morton Arboretum, Illinois, US. Acc. nos. 1302-27, 446-48, 492-64, 27-98.


Ulmus minor Mill., the field elm, is by far the most polymorphic of the European species, although its taxonomy remains a matter of contention. Its natural range is predominantly south European, extending to Asia Minor and Iran; its northern outposts are the Baltic islands of Öland and Gotland, although it may have been introduced here by man. The tree's typical habitat is low-lying forest along the main rivers, growing in association with oak and ash, where it tolerates summer floods as well as droughts.
Current treatment of the species owes much to Richens, who noted (1983) that several varieties of field elm are distinguishable on the European mainland. Of these, he listed the small-leaved U. minor of France and Spain; the narrow-leaved U. minor of northern and central Italy; the densely hairy leaved U. minor of southern Italy and Greece; the U. minor with small-toothed leaves from the Balkans; the U. minor with large-toothed leaves from the Danube region; and the small-leaved U. minor from southern Russia and Ukraine. As for British varieties, "the continental populations most closely related [to eastern English Field Elm] are in central Europe", while south-western forms were introduced from France. He concluded, however, that owing to incomplete field-research at the time of writing, it was "not possible to present an overall breakdown of the European Field Elm into regional varieties". The epithet 'red' elm was commonly used by British foresters, an allusion to the colour of the timber.
Richens sank a number of British elms, notably English elm, as either subspecies or varieties of U. minor in 1968. However, Melville, writing ten years later, identified five distinct species (including U. glabra in the count), several varieties and numerous complex hybrids.  In 1992 Armstrong identified no fewer than forty British species and microspecies. Clive Stace (1997) wrote of the British elms "The two-species (glabra and minor) concept of Richens is not sufficiently discriminating to be of taxonomic value". Nevertheless, it is Richens’ classification which has been the most commonly adopted in recent years, although it is not used in Flora Europaea .
In 2009 Dr Max Coleman of the Royal Botanic Garden, Edinburgh wrote: "The advent of DNA fingerprinting has shed considerable light on the question. A number of studies have now shown that the distinctive forms Melville elevated to species and Richens lumped together as field elm are single clones, all genetically identical, which have been propagated by vegetative means such as cuttings or root suckers. This means that enigmatic British elms such as Plot elm and English elm have been shown to be single clones of field elm. Although Richens did not have the evidence to prove it, he was correct in recognising a series of clones and grouping them together as a variable species."
It is hoped that analysis of molecular markers will ultimately eliminate the taxonomic confusion.


The tree typically grows to < 30 m (98 ft) and bears a rounded crown. The bark of the trunk is rough, furrowed lightly in older trees to form a block pattern. Young branchlets occasionally have corky wings. The shoots are slender compared with those of wych elm. The leaves are smaller than those of the other European species, hence the specific epithet minor, however they can vary greatly according to the maturity of the tree. Leaves on juvenile growth (suckers, seedlings etc.) are coarse and pubescent, whereas those on mature growth are generally smooth, though remaining highly variable in form; there are generally fewer than 12 pairs of side veins. A common characteristic is the presence of minute black glands along the leaf veins, detectable with the aid of a magnifying glass.  The samarae are oval or obovate, glabrous, 12–15 mm (15⁄32–19⁄32 in) long, notched at the top, with the seed close to the notch. Ulmus minor in France generally begins to flower and fruit when aged 10 years.
The species readily produces suckers from roots and stumps, even after devastation by Dutch elm disease; consequently genetic resources are not considered endangered .


The species has a hugely variable reaction to Dutch elm disease (DED), including all the fashionable pre-20th century plantsman's clones (see Subspecies and varieties). However, field elm is genetically highly variable; Italian specimens when inoculated with the pathogen displayed between 15 and 100% dieback and between 70 and 100% wilting, whereas with trees tested in Spain, the variability ranged from 5 to 100% dieback, and 20 to 95% wilting. In 2013 researchers at the Universidad Politėcnica de Madrid announced the discovery and cloning of trees in Spain with levels of resistance greater than 'Sapporo Autumn Gold' (see Cultivation).
Tolerance of elm yellows (phloem necrosis) is generally good, U. minor exhibiting symptoms such as the 'witch's broom' only sporadically throughout Italy, including Sicily and Sardinia, however the disease was often locally common within the species in France, including Paris.


U. minor in general and a number of clones in particular (see 'Cultivars' below) were once commonly cultivated across Europe in town and country, but owing to its susceptibility to Dutch elm disease, U. minor is now uncommon in cultivation. However, in an ongoing project that began in the 1990s, several thousand surviving field elms have been tested for innate resistance by national research institutes in the EU, with a view to returning field elm to cultivation. Results from Spain (2013), for example, confirm that a very small number of surviving field elms (about 0.5% of those tested) appear to have comparatively high levels of tolerance of the disease, and it is hoped that a controlled crossing of the best of these will produce resistant Ulmus minor hybrids for cultivation.
In the UK, despite its late leaf-flush in the north and its suckering habits, continental U. minor was occasionally planted as an ornamental urban tree. Augustine Henry wrote in 1913 that the U. minor planted in parks in Scotland were of French origin. More recently U. minor seed was imported to the UK from Italy. There are mature survivors in Edinburgh that are not the common U. minor cultivars (2015).
U. minor has been introduced to the southern hemisphere, notably Australasia and Argentina.


U. minor can live to a great age. An ancient field elm stood until recently in the village square of Metaxades, Thrace, Greece. Having abandoned their original village in 1286 after cholera outbreaks, the villagers re-founded it in the hills where a young elm was growing beside a spring. An elm (reputedly the original) and the fountain were the focal-point of the village until the late 20th century. The tallest recorded field elms in Greece were two specimens planted in 1650 beside the newly built church of the Archangels Michael and Gabriel, in Omali Voiou (Oμαλή Bοΐου) near Siatista, which, despite being open-grown trees, attained a height of 40 metres by the mid-20th century. The immemorial elm opposite the village square of Aidona in Thessaly, Greece which has been "listed" as a national "Monument of Nature", lost its crown in a recent storm (2009) and has now been pollarded; it is regenerating vigorously. A rare example of a centuries-old field elm that retains its heartwood and crown is the 360-year-old specimen in the village square of Strinylas, Corfu.
A tree said to be of similar age (200 cm d.b.h.) still stands (2013) in the city of Sliven, Bulgaria; other veterans are said to survive in the village of Samuilovo, 7 km from Sliven.
In France, a tree reputedly over 650 years old survived in the centre of Biscarrosse south of Bordeaux until the summer of 2010, when it finally succumbed to Dutch elm disease. Another veteran with a 6-metre girth survives at Bettange, France, close to the Belgian border, reputedly planted in 1593. Other wrecks include 'l'ormeau de Sully' in Villesèquelande near Carcassonne, "a magnificent tree supported by three metal props", said to have been planted in the early 17th C by the Duc de Sully,
A tree approximately 400 years old and 5.55 metres in girth grows in the town of Mergozzo in Piedmont, Italy. 'L'olmo di Mergozzo', like its French counterparts 'l'orme de Biscarosse' and 'l’orme de Bettange', is hollowed out by age, its life prolonged by lopping, while in Spain the elm in the Plaza del Olmo in Navajas, Valencia, is 6.3 metres in girth; planted in 1636 it features on the town crest.
In England, large specimens once identified as U. minor subsp. minor, the narrow- or smooth-leafed elm, were once commonplace in the eastern counties before the advent of DED. The largest recorded tree in the UK grew at Great Amwell, Hertfordshire,  measuring 40 m in height and 228 cm d.b.h. in 1911. Another famous specimen was the great elm that towered above its two siblings at the bottom of Long Melford Green, Long Melford, Suffolk, till the group succumbed to disease in 1978. The three "were survivors of a former clone of at least nine elms, one dating from 1757". The Long Melford elms were painted in 1940 by the watercolourist S. R. Badmin in his 'Long Melford Green on a Frosty Morning', now in the Victoria and Albert Museum. The largest known surviving trees in England are at East Coker, Somerset (30 m high, 95 cm d.b.h.), Termitts Farm near Hatfield Peverel, Essex (25 m high, 145 d.b.h.), and Melchbourne, Bedfordshire, (147 cm d.b.h.).


The name Ulmus minor subsp. minor was used by R. H. Richens for field elm that was not English elm, Cornish elm, Plot elm or Guernsey elm. Many publications, however, continue to use plain Ulmus minor for undifferentiated field elm; indeed Dr Max Coleman of Royal Botanic Garden Edinburgh argued in his 2002 paper 'British Elms' that there was no clear distinction between species and subspecies. Some authorities, among them Richens and Coleman, include English elm among varieties of field elm, Richens calling English elm U. minor var. vulgaris. Richens sank as undifferentiated U. minor certain local English forms such as U. minor 'Goodyeri', U. minor 'Hunnybunii', U. minor 'Sowerbyi', and U. minor 'Coritana'.


Henry's Ulmus nitens var. italica, 'Mediterranean Elm' (1913), distinguished by its 14 to 18 pairs of leaf-veins, was accepted, despite the wide source-area claimed for it ("Italy, Spain, Portugal and Algeria"), as U. carpinifolia var. italica Henry, by Krüssman (1984), who included a photograph of a specimen in Gisselfeld Park, Denmark. Bean (1988), however, considered it "a variety of rather dubious standing", and it was ignored by Richens (1983).
U. canescens Melville and U. boissieri Grudz. were both sunk as U. minor by Richens. The former is found throughout the eastern Mediterranean, including Israel, and is distinguished by its leaves, densely downy on the underside when mature.  The latter is a little-known tree found in Iran, in the Zagros forests and the Kerman / Kermanshah area.Green and Richens also sank U. minor var. suberosa (Moench) Rehder - the so-called 'Cork-barked elm', korkulme (Germany) or wiąz korkowa (Poland), as a genetically random, maritime or juvenile form of U. minor, insufficiently differentiated to merit varietal status, its name a relic of taxonomic conservatism.


Numerous cultivars have been raised in Europe since the 18th century, although many are now probably either extinct owing to the ravages of Dutch elm disease, or survive unrecognized in sucker form:
Ademuz
Albo-Dentata
Amplifolia
Argenteo-Variegata
Atinia
Atinia Pyramidalis
Atinia Variegata
Bea Schwarz
Biltii
Christine Buisman
Concavaefolia
Coritana
Corky Cloud
Cretensis
Cucullata
Cucullata Variegata
Dehesa de Amaniel
Dehesa de la Villa
Dicksonii
Dijkwel
Erecta
Folia Alba-Punctata
Glandulosa
Goodyeri
Hoersholmiensis
Holmstruph
Hunnybunii
Hunnybunii pseudo-Stricta
Jos van Slycken
Laciniata
Lanuginosa
Majadahonda
Microphylla Pendula
Microphylla Purpurea
Microphylla Rubra
Monumentalis
Pendula
Picturata
Plotii
Propendens
Punctata
Purpurascens
Purpurea
Retiro
Reverti
Rugosa
Rueppellii
Sarniensis
Schuurhoek
Silvery Gem
Sowerbyi
Stricta
Suberosa
Umbraculifera
Umbraculifera Gracilis
Viminalis
Viminalis Aurea
Viminalis Betulaefolia
Viminalis Gracilis
Viminalis Incisa
Viminalis Marginata
Viminalis Pendula
Viminalis Pulverulenta
Viminalis Stricta
Virgata
Webbiana


The tree's natural range generously overlaps that of wych elm Ulmus glabra to the north, and readily hybridizes with it to produce the so-called 'Dutch elm' Ulmus × hollandica.
In Spain and Italy Ulmus minor has naturally hybridized with Siberian elm U. pumila, which was introduced in the 16th century and which has spread widely since then, contributing to conservation concerns for the former species. The resulting hybrid has not yet been given a formal botanical name, though there are cultivated forms such as 'Recerta' and 'Fiorente' (see Hybrid cultivars).
Ulmus × hollandica
U. minor × U. pumila


U. minor hybridises naturally with U. glabra, producing elms of the Ulmus × hollandica group, from which there have arisen a number of cultivars:
Alba
Angustifolia
Balder
Belgica
Blandford
Canadian Giant
Cicestria
Cinerea
Commelin
Dampieri
Dauvessei
Daveyi
Dumont
Elegantissima
Eleganto-Variegata
Etrusca
Fastigiata
Fjerrestad
Folia Rhomboidea
Freja
Fulva
Gaujardii
Groeneveld
Haarlemensis
Klemmer
Loke
Macrophylla Aurea
Major
Microphylla
Modiolina
Muscaviensis
Nottingham
Odin
Pioneer
Pitteurs
Serpentina
Smithii
Superba
Tricolor
Tyr
Vegeta
Viminalis
Viscosa
Wentworthii Pendula
Wredei
Ypreau
The tree has featured strongly in artificial hybridization experiments in Europe and to a lesser extent in the United States. Most of the European research was based at Wageningen in the Netherlands until 1992, whence a number of hybrid cultivars have been commercially released since 1960. The earlier trees were raised in response to the initial Dutch elm disease pandemic that afflicted Europe after the First World War, and were to prove vulnerable to the much more virulent strain of the disease that arrived in the late 1960s. However, further research eventually produced several trees highly resistant to disease which were released after 1989.
Arno, Clusius, Columella, Commelin, Den Haag, Fiorente, Frontier, Fuente Umbria, Groeneveld, Homestead, Lobel, Nanguen = Lutèce, Pioneer, Plantyn, Plinio, Recerta, San Zanobi, Toledo, Urban, Wanoux = Vada


Eastwoodhill Arboretum , Gisborne, New Zealand. 2 trees, details not known.


Ulmus parvifolia, commonly known as the Chinese elm or lacebark elm, is a species native to eastern Asia, including China, India, Japan, North Korea, and Vietnam. It has been described as "one of the most splendid elms, having the poise of a graceful Nothofagus".
The tree was introduced to the UK in 1794 by James Main, who collected in China for Gilbert Slater of Low Layton, Essex.


A small to medium deciduous, semi-deciduous (rarely semi-evergreen) tree growing to 10–18 m (33–59 ft) tall and 15–20 m (49–66 ft) wide with a slender trunk and crown. The leathery, lustrous green single-toothed leaves are small, 2–5 cm long by 1–3 cm broad, and often retained as late as December or even January in Europe and North America. The apetalous wind-pollinated perfect flowers are produced in early autumn, small and inconspicuous. The fruit is a samara, elliptic to ovate-elliptic, 10–13 mm long by 6–8 mm broad. The samara is mostly glabrous, the seed at the centre or toward the apex, borne on a stalk 1–3 mm in length; it matures rapidly and disperses by late autumn. The trunk has a handsome, flaking bark of mottled greys with tans and reds, giving rise to its other common name, the lacebark elm, although scarring from major branch loss can lead to large canker-like wounds. Ploidy: 2n = 28."SaylorPlants.com - Chinese Elm, Lacebark Elm ( Ulmus  parvifolia )". www.saylorplants.com. Archived from the original on 16 July 2011. Retrieved 22 May 2022.</ref>
Many nurserymen and foresters mistakenly refer to Ulmus pumila, the rapidly growing, disease-ridden, relatively short-lived, weak-wooded Siberian elm, as "Chinese elm." This has given the true Chinese elm an undeserved bad reputation. The two elms are very distinct and different species. The Siberian elm's bark becomes deeply ridged and furrowed with age, among other obvious differences. It possesses a very rough, greyish-black appearance, while the Chinese elm's smooth bark becomes flaky and blotchy, exposing very distinctive, light-coloured mottling, hence the synonym lacebark elm for the real Chinese elm.


Subspecies, varieties, and forms:
Ulmus parvifolia var. coreana Nakai
Ulmus parvifolia f. lanceolata Ueki


The Chinese elm is highly resistant, but not immune, to Dutch elm disease. It is also very resistant to the elm leaf beetle Xanthogaleruca luteola, but has a moderate susceptibility to elm yellows. In trials at the Sunshine Nursery, Oklahoma, the species was adjudged as having the best pest resistance of about 200 taxa  However, foliage was regarded as only "somewhat resistant" to black spot by the Plant Diagnostic Clinic of the University of Missouri.
Cottony cushion scale or mealy bugs, often protected and "herded" by ants, exude sticky, sweet honeydew which can mildew leaves and be a minor annoyance by dripping on cars and furniture. However, severe infestations on or obvious damage to otherwise healthy trees are uncommon.
In some regions of the southern United States, a fungus known as Phymatotrichopsis omnivora is known to cause sudden death of lacebark elms when infected.


The Chinese elm is a tough landscape tree, hardy enough for use in harsh planting situations such as parking lots, small planters along streets, and plazas or patios. The tree is arguably the most ubiquitous elm, now found on all continents except Antarctica. It was introduced to Europe at the end of the 18th century as an ornamental and is found in many botanical gardens and arboreta. It was introduced to the United States in 1794, and has proved very popular in recent years as a replacement for American elms killed by Dutch elm disease. The tree was distributed in Victoria, Australia, from 1857. At the beginning of the 20th century Searl's Garden Emporium, Sydney marketed it. In New Zealand, it was found to be particularly suitable for windswept locations along the coast. The tree is commonly planted as an ornamental in Japan, notably around Osaka Castle.
Ulmus parvifolia is one of the cold-hardiest of the Chinese species. In artificial freezing tests at the Morton Arboretum. the LT50 (temp. at which 50% of tissues die) was found to be −34 °C (−29 °F).


Numerous cultivars have been raised, mostly in North America:
A. Ross Central Park = Central Park Splendor
BSNUPF = Everclear
Blizzard
Burgundy
Burnley Select
Catlin
Chessins
Churchyard
Cork Bark
D.B.Cole
Drake
Dynasty
Ed Wood
Elsmo
Emer I or Emerald Isle = Athena
Emer II or Emerald Vase = Allee
Emerald Prairie
Frosty
Garden City Clone
Geisha
Glory
Golden Rey
Hallelujah
Harzam = Harrison
Hokkaido
Jade Empress
King's Choice
Littleleaf
Lois Hole
Matthew
Milliken
Nire-keyaki
Ohio
Orange Ribbon
Pathfinder
Pendens
Prairie Shade
Prince Richard
Red Fall
Sabamiki
Sagei
Seiju
Select 380
Sempervirens
Small Frye
State Fair
Stone's Dwarf
Taiwan
The Thinker
Todd
UPMTF = Bosque
Ware's
Yarralumla
Yatsubusa
Zettler =  Heritage


An autumn flowering species, whereas most other elms flower in spring. Hybrids have accordingly been very few:
Frontier
Rebella


North America
Arnold Arboretum, US. Acc. nos. 1353-73, 17917, 195-90, 197-90.
Bartlett Tree Experts, US. Acc. nos. 5546, 8109.
Brenton Arboretum, Dallas Center, Iowa, US. No details available.
Brooklyn Botanic Garden, New York, US. Acc. nos. 000880, 160001, 20020466, 850222, X00450, X00485, X02727, X02771.
Chicago Botanic Garden, US. 2 trees, no other details available.
Dominion Arboretum, Ottawa, Ontario, Canada. No acc. details.
Fullerton Arboretum, California State University, US. Acc. no. 80-036.
Holden Arboretum, US. Acc. nos. 57-1241, 80-665, 84-1214, 90-323.
Longwood Gardens, US. Acc. nos. 1957-1058, 1959-1500, 1960-1138, 1991-0981.
Missouri Botanical Garden, St. Louis, US. Acc. nos. 1986-0108, 1986-0276, 1986-0277, 1987-0019, 199-3195, 1996-3462.
Morris Arboretum, University of Pennsylvania, US. Acc. no. 32-0052-A.
Morton Arboretum, US. Acc. nos. 991-27, 772-54, 1231–57, 558-83, 52-96.
New York Botanical Garden, US. Acc. nos. 195/56, 486/91, 68072.
Phipps Conservatory, US. Acc. nos. 83-006, 83-058, 91-050, 2001-212UN.
Scott Arboretum, US. Acc. nos. 62210, 71765, 71767, 71771, 75152, 64441.
Smith College, US. Acc. no. 42894.
U S National Arboretum, Washington, D.C., US. Acc. nos. 58000/1/2/3/4/5/6/7/8.
Europe
Brighton & Hove City Council, UK. NCCPG Elm Collection.
Cambridge Botanic Garden, University of Cambridge, UK. No accession details available.
Dyffryn Gardens, Glamorgan. UK champion, 13 m high, 37 cm d.b.h., last surveyed 1997.
Grange Farm Arboretum, Sutton St. James, Spalding, Lincolnshire, UK. Acc. no. 516.
Great Fontley Butterfly Conservation Elm Trials plantation, UK. One seedling planted 2019.
Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18150, 18151.
Linnaean Gardens of Uppsala, Sweden. Acc. no. 2002-1542.
Royal Botanic Gardens Kew. Acc. nos. 1979-1613, 1979-1614, 1982–8479, 1982-8505, 1982-6280, 1982-6284, 2002-137, 2003-1267, 2005-1076.
Royal Botanic Gardens Kew Wakehurst Place, UK. Acc. nos. 1969-33664, 1969-35133, 1973-21049, 1973-21525.
Royal Horticultural Society Gardens, Wisley, UK. No details are available.
Wijdemeren City Council Elm arboretum: 4 cv. ‘UPMTF’ planted Molenmeent Loosdrecht in 2017.
Strona Arboretum, University of Life Sciences, Warsaw, Poland. No accession details are available.
Tallinn Botanic Garden, Estonia. No accession details available.
Thenford House arboretum, Banbury, UK. No details are available.
University of Copenhagen Botanic Garden. Denmark. Acc. nos. S1956-1338, S1997-1304.
Westonbirt Arboretum, Tetbury, Glos., UK. Planted 1981. No acc. no.
Australasia
Eastwoodhill Arboretum, Gisborne, New Zealand. 9 trees, details not known.


Ulmus pumila, the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese Elm' (Ulmus parvifolia). U. pumila has been widely cultivated throughout Asia, North America, Argentina, and southern Europe, becoming naturalized in many places, notably across much of the United States.


The Siberian elm is usually a small to medium-sized, often bushy, deciduous tree growing to 25 metres (82 feet) tall, the diameter at breast height to 1 m (3 ft 3 in). The bark is dark gray, irregularly longitudinally fissured. The branchlets are yellowish gray, glabrous or pubescent, unwinged and without a corky layer, with scattered lenticels. The winter buds dark brown to red-brown, globose to ovoid. The petiole is 4–10 millimetres (1⁄4–1⁄2 inch), pubescent, the leaf blade elliptic-ovate to elliptic-lanceolate, 2–8 by 1.2–3.5 centimetres (3⁄4 in–3+1⁄8 in × 1⁄2 in–1+3⁄8 in), the colour changing from dark green to yellow in autumn. The perfect, apetalous wind-pollinated flowers bloom for one week in early spring, before the leaves emerge, in tight fascicles (bundles) on the last year's branchlets. Flowers emerging in early February are often damaged by frost (causing the species to be dropped from the Dutch elm breeding programme). Each flower is about 3 mm (1⁄8 in) across and has a green calyx with 4–5 lobes, 4–8 stamens with brownish-red anthers, and a green pistil with a two-lobed style. Unlike most elms, the Siberian elm is able to self-pollinate successfully.
The wind-dispersed samarae are whitish tan, orbicular to rarely broadly obovate or elliptical, 1 cm–2 cm × 1 cm–1.5 cm (3⁄8 in–3⁄4 in × 3⁄8 in–5⁄8 in), glabrous except for pubescence on stigmatic surface; the stalk 1–2 mm (5⁄128–5⁄64 in), the perianth persistent. The seed is at centre of the samara or occasionally slightly toward apex but not reaching the apical notch. Flowering and fruiting occur March to May. Ploidy: 2n = 28. The tree also suckers readily from its roots.
The tree is short-lived in temperate climates, rarely reaching more than 60 years of age, but in its native environment may live to between 100 and 150 years. A giant specimen, 45 kilometres (28 miles) southeast of Khanbogt in the south Gobi, with a girth of 5.55 m (18 ft 3 in) in 2009, may exceed 250 years (based on average annual ring widths of other U. pumila in the area).


The tree is native to Central Asia, eastern Siberia, the Russian Far East, Mongolia, Tibet, northern China, India (northern Kashmir) and Korea. It is the last tree species encountered in the semi-desert regions of Central Asia.


The tree has considerable variability in resistance to Dutch elm disease; for example, trees from north-western and north-eastern China exhibit significantly higher tolerance than those from central and southern China. Moreover, it is highly susceptible to damage from many insects and parasites, including the elm leaf beetle Xanthogaleruca luteola, the Asian 'zigzag' sawfly Aproceros leucopoda, Elm Yellows, powdery mildew, cankers, aphids, leaf spot and, in the Netherlands, coral spot fungus Nectria cinnabarina. U. pumila is the most resistant of all the elms to verticillium wilt.


In North America, Ulmus pumila has become an invasive species in much of the region from central Mexico northward across the eastern and central United States to Ontario, Canada. It also hybridizes in the wild with the native U. rubra (slippery elm) in the central United States, prompting conservation concerns for the latter species. In South America, the tree has spread across much of the Argentine pampas.
In Europe it has spread widely in Spain, and hybridizes extensively there with the native field elm (U. minor), contributing to conservation concerns for the latter species.  Research is ongoing into the extent of hybridisation with U. minor in Italy.
Ulmus pumila is often found in abundance along railroads and in abandoned lots and on disturbed ground.  The gravel along railroad beds provides ideal conditions for its growth: well-drained, nutrient poor soil, and high light conditions; these beds provide corridors which facilitate its spread.  Owing to its high sunlight requirements, it seldom invades mature forests, and is primarily a problem in cities and open areas, as well as along transportation corridors.
The species is now listed in Japan as an alien species recognized as established in Japan or found in the Japanese wild.


U. pumila was introduced into Spain as an ornamental, probably during the reign of Philip II (1556–98), and from the 1930s into Italy. In these countries it has naturally hybridized with the field elm (U. minor). In Italy it was widely used in viniculture, notably in the Po valley, to support the grape vines until the 1950s, when the demands of mechanization made it unsuitable.
Three specimens were supplied by the Späth nursery of Berlin to the Royal Botanic Garden Edinburgh (RBGE) in 1902 as U. pumila, in addition to specimens of the narrow-leaved U. pumila cultivar 'Pinnato-ramosa'. One was planted in RBGE; the two not planted in the Garden may survive in Edinburgh, as it was the practice of the Garden to distribute trees about the city. Kew Gardens obtained specimens of U. pumila from the Arnold Arboretum in 1908 and, as U. pekinensis, via the Veitch Nurseries in 1910 from William Purdom in northern China. A specimen obtained from Späth and planted in 1914 stood in the Ryston Hall arboretum, Norfolk, in the early 20th century. The tree was propagated and marketed by the Hillier & Sons nursery, Winchester, Hampshire, from 1962 to 1977, during which time over 500 were sold. More recently, the popularity of U. pumila in the Great Britain has been almost exclusively as a bonsai subject, and mature trees are largely restricted to arboreta. In the UK the TROBI Champions grow at Thorp Perrow Arboretum, Yorkshire, 19 m (62 ft 4 in) × 70 cm (2 ft 4 in) in 2004, and at St Ann's Well Gardens, Hove, Sussex 20 m (65 ft 7 in) × 60 cm (2 ft 0 in) in 2009.
U. pumila is said to have been introduced to the US in 1905 by Prof. John George Jack, and later by Frank Nicholas Meyer, though 'Siberian elm' appears in some 19th-century US nursery catalogues. The tree was cultivated at the United States Department of Agriculture (USDA) Experimental Station at Mandan, North Dakota, where it flourished. It was consequently selected by the USDA for planting in shelter belts across the prairies in the aftermath of the Dustbowl disasters, where its rapid growth and tolerance for drought and cold initially made it a great success. However, the species later proved susceptible to numerous maladies. Attempts to find a more suitable cultivar were initiated in 1997 by the Plant Materials Center of the USDA, which established experimental plantations at Akron, Colorado, and Sidney, Nebraska. The study, no. 201041K, will conclude in 2020. The US National Champion, measuring 33.5 m (109 ft 11 in) high in 2011, grows in Berrien County, Michigan.
The seeds lose their viability rapidly after maturity unless placed on suitable germination conditions or dried and placed at low temperatures. The species has a high sunlight requirement and is not shade-tolerant; with adequate light it exhibits rapid growth.  The tree is also fairly intolerant of wet ground conditions, growing better on well-drained soils. While it is very resistant to drought and severe cold, and able to grow on poor soils, its short period of dormancy, flowering early in spring followed by continuous growth until the first frosts of autumn, renders it vulnerable to frost damage.
As an ornamental U. pumila is a very poor tree, tending to be short-lived, with brittle wood and poor crown shape, but it has nevertheless enjoyed some popularity owing to its rapid growth and provision of shade. The Siberian Elm has been described as "one of the world's worst...  ornamental trees that does not deserve to be planted anywhere". Yet in the US during the 1950s, the tree was also widely promoted as a fast-growing hedging substitute for privet, and as a consequence is now commonly found in nearly all states.


Valued for the high resistance of some clones to Dutch elm disease, over a dozen selections have been made to produce hardy ornamental cultivars, although several may no longer be in cultivation:
Ansaloni
Aurea = Beijing Gold
Aurescens
Chinkota
Dropmore
Dwarf Weeper
Green King
Hansen
Harbin
Manchu
Mauro
Mopheads
Mr. Buzz
Park Royal
Pendula
Pinnato-ramosa
Poort Bulten
Puszta
Pyramidalis Fiorei
Zhonghua Jinye

Some authorities consider the cultivar 'Berardii' a form of U. pumila.


The unripe seeds have long been eaten by the peoples of Manchuria, and during the Great Chinese Famine they also became one of the most important foodstuffs in the Harbin region. The leaves were also gathered, to the detriment of the trees, prompting a prohibition order by the authorities, which was largely ignored. The leaves eaten raw are not very palatable, but stewed and prepared with Kaoliang or Foxtail millet make a better tasting and more filling meal.


The "dwarf-" or "shrub-elms" of the North Caucasus, along with other local flora, appear in the opening description of Tolstoy's story 'The Raid' (1853).
Nicholas Roerich describes a specimen discovered on his travels through Mongolia:
We are in the deserts of Mongolia. It was hot and dusty yesterday. From faraway thunder was approaching. Some of our friends became tired from climbing the stony holy hills of Shiret Obo. While already returning to the camp, we noticed in the distance a huge elm tree – 'karagatch', - lonely, towering amidst the surrounding endless desert. The size of the tree, its somewhat familiar outlines attracted us into its shadow. Botanical considerations led us to believe that in the wide shade of the giant there might be some interesting herbs. Soon, all the co-workers gathered around the two mighty stems of the karagatch. The deep, deep shadow of the tree covered about 50 feet across. The powerful tree-stems were covered with fantastic burr growths. In the rich foliage, birds were singing and the beautiful branches were stretched out in all directions, as if wishing to give shelter to all pilgrims.


Alma Park, St Kilda, Victoria, Australia. One specimen, listed on the National Trust of Victoria's Significant Tree Register.
Eastwoodhill Arboretum , Gisborne, New Zealand. 2 trees, details not known.


Ulmus thomasii, the rock elm or cork elm, is a deciduous tree native primarily to the Midwestern United States. The tree ranges from southern Ontario and Quebec, south to Tennessee, west to northeastern Kansas, and north to Minnesota.


The tree was named in 1902 for David Thomas, an American civil engineer who had first named and described the tree in 1831 as Ulmus racemosa.