Amsonia is a relatively small genus with a few species that offer outstanding ornamental value. One of the loveliest, Amsonia tabernaemontana, is easier to cultivate than to pronounce. Luckily, this gorgeous plant with its dense clusters of elegant star-shaped blue flowers is also known as Eastern Bluestar, which is an awful lot easier to remember!
Amsonia tabernaemontana is a rarely seen, easy to grow perennial that has a long flowering period and gives reliable performance year after year. With an upright bushy habit it grows to a height of around 70 to 80cm (28 to 32in) and a spread of 45cm (18in). The plants form tight clumps that do not need regular division or staking, they grow happily in sun or dappled shade and cope well with drought.
The blue star shaped flowers are loosely held in slightly pendulous clusters on top of tall stems that can be cut and used in floral arrangements. The slender, tapering dark green leaves turn interesting golden-yellow shades before dying back in autumn.
Amsonia tabernaemontana will create a massive impact when their dark blue flower buds open to reveal their elegant blue flowers in spring and summer, and will provide shining colour in autumn. Long-lived and adaptable, this attractive and unusual addition to the border warrants more inclusion in our gardens.
Amsonias prefer moist soils and grow well in any garden soil, including clay. They will grow in full sun or semi-shade. The plants are drought tolerant and generally do not wilt in dry spells. Drier conditions reduce the height of the plant, but they will flower well every year. In drier situations they are happiest in semi-shade.
Amsonia germinate best if they experience a cold period. If you are planting in autumn to winter you can use the natural method, simply planting in a seed tray and placing the tray outdoors until the spring. Otherwise, at warmer times of the year it will be necessary to artificially simulate winter temperatures by using the method of stratification.
Fill 7cm (3in) pots or trays with a good soil-based compost. Sow the large seeds onto the surface and gently firm down. Cover the seeds with a sprinkling of fine grit.
The Natural Method: Autumn / Winter
Fill seed trays with a good soil-based compost. Sow the large seeds onto the surface and gently firm down. Cover the seeds with a sprinkling of fine grit. Place the tray or pots in a cold frame, an unheated greenhouse or under a shaded hedge. Keep the soil damp but not wet and do not exclude light. Patience may be needed as germination can be very slow taking anything from 30 to 365 days, although germination can be quicker if temperatures are around 15 to 20°C (16 to 68°F). When seedlings are large enough to handle, transplant them into 7cm (3in) pots and grow them on in cooler conditions until large enough to move outdoors. Keep the seedlings in light, but not full sun and plant out in autumn.
Stratification: Spring / Summer
If you require seedlings quicker, you may wish to try stratifying the seeds – this method simply exposes the seedlings to temperature changes, as they would do if germinating naturally.
Sow the large seeds onto the surface of trays or pots containing good soil based compost and gently firm down. Place in a propagator or seal inside a polythene bag and keep at a daytime temperature of 13 to 15°C (55 to 60°F) for 2 to 3 weeks. After this time, move the tray to a refrigerator to cool (not a freezer) this will expose the seeds to temperatures of around 4°C (39°F) which will simulate the cold of winter. Leave them in the fridge for 3 to 6 weeks, after which remove the tray and place somewhere with normal daytime temperatures. Keep the compost moist at all times.
This method usually works for some of the seedlings but some seeds may wait for spring before emerging regardless of when or how they are sown. Prick out any seedlings that have germinated into pots to grow on, then place the tray back in the cold frame so that any seeds that remain may germinate naturally.
Plant Amsonia at a distance of 30cm (12in) apart, in any well-drained soil in sun or dappled shade.
Amsonias plants are slow to get going in the garden, these slow-growing perennials form tight clumps that do not need regular division or staking. They can, if needed be divided in early autumn and replanted straight into the soil.
Due to their milky sap, Amsonias are often bypassed by foraging mammals, which makes them somewhat resistant to deer and other pests. Although they only contains two to five per cent latex which can irritate the skin, this slight toxicity has one major advantage - slugs and snails never damage the emerging shoots.
The flowers can be cut and used in floral arrangements, wear gloves and sear the end of the stems in a flame to stem the milky sap before popping in a vase.
Amsonias have some of the funniest-looking seeds around. The seed pods are long tubes that are filled with cylindrical brown seeds arranged end-to-end. The seeds ripen in late summer to autumn, quite a long time after the plants bloom. Harvest them when the pods are quite dry and tan in colour, but before they split apart lengthwise to drop their seeds. They germinate quickly when sown straight away. If stored, the seeds may need to go through a cold season before germination.
Cottage gardens, Borders and beds, Low maintenance gardens, Shade and Woodland gardens.
Amsonia is a genus of about twenty species, native to temperate climates in North America, Europe, and Asia. It occurs in moist to wet woods, floodplains, and riverbanks.
The flowers of each species are, at least superficially quite similar, as are the seedpods. For most of the year, the leaves and branching structure provide the best clues to tell the different species apart.
The latest taxonomical wisdom places them in the apocynaceae family, which they share with several hundred other genera, including Asclepias and Vinca.
The genus Amsonia is named for Charles Amson, a U.S. traveler-scientist who lived in the 18th century.
The species name if for Jacob Theodor Tabernamontanus, a physician and an early botanist and herbalist, the 'Father of German Botany'. The French botanist Charles Plumier erected the genus, as a compliment to Tabernaemontanus, and it was adopted by Linnaeus.
It is commonly called Eastern Bluestar or Woodland Bluestar and can occasionally be found with the name Willow Amsonia, due to the lance shaped leaves, which are wider than most other species.
Jacob Theodor Tabernaemontanus:
Jacobus Theodorus (Jakob Dietrich) Tabernaemontanus (von Bergzabern) (1525-1590) was a physician and an early botanist and herbalist, the 'Father of German Botany' whose illustrated Neuwe Kreuterbuch (1588) or Eicones Plantarum (Frankfurt, 1590) was the result of a lifetime's botanising and medical practice. It provided unacknowledged material for John Gerard's better-known Herball (London, 1597) and was reprinted in Germany throughout the 17th century.
His Latinised name Tabernamontanus, represented a translation of his native town Bergzabern and literally means ‘mountain tavern’. Bergzabern is situated in the Rhineland-Palatinate region of Germany near the border with France, on the south-eastern edge of the Palatinate forest.
Tabernaemontanus began as a student of the pioneer of Renaissance botany, Hieronymus Bock. His career was supported in the usual manner of his time, by a series of places as court physician to German nobles. In 1549 he was the private doctor to Philip III, Count of Nassau-Weilburg and later to Marquard von Hattstein, bishop of Speyer. Later he served as town physician to the free imperial city of Worms, Germany.
He studied with Bock in Heidelberg, where he spent the last decades of his life, in Bock's footsteps, as physician to his liege lord, the Prince-Elector and where he died, having been three times married and the father eighteen children.
He is commemorated in the pan-tropical genus of flowering shrubs Tabernaemontana.
Tabernaemontanus was perhaps the most scholarly of the writers on beer and brewing. His botanical encyclopedia included a broad range of information about beer: how it was made, how to make it better and what should be avoided. While he did explain the process, stating specific times that beer should be boiled to get the healthiest product, what interested him most were the plants used as additives. Hops were the standard but he mentions that the English often suspended a mixture of sugar, cinnamon, cloves and other spices in a sack in the beer.
Brewing was firmly established as an important industry and with increasing competition between breweries and growing demand for their beverages, brewers became interested in reaping profits than in making a good product. Many northern European brewers were turning out beer of unpredictable quality. A criticism of Rhineland brewing voiced by Tabernaemontanus in 1588, is evidence of the publics dissatisfaction:
'In some towns on the Rhine, beer is now made, such that it is a pity to spoil good grain thus, for the people only get the value of half the beer, because when they have drunk half a cask, the bottom has become so spoiled and sour that it has to be wasted. It has three great defects - too little malt is used, too much water, and it is not boiled.
I do not mention the other trick which is practiced - that instead of hops, some take willow leaves, and chimney soot, which gives the beer a strong brick red colour. Not only does such a beer not taste good, but spoils the blood, burns it up, causes great thirst, horrible red faces, also leprosy, swelling of the body, injury to the head and all internal parts of the intestines'.
- Additional Information
Average Seed Count 20 Seeds Family Apocynaceae Genus Amsonia Species tabernaemontana Cultivar Blue Star Common Name Eastern Bluestar, Willow Amsonia Other Common Names Woodland Bluestar Hardiness Hardy Perennial Flowers Blue star shaped flowers Natural Flower Time May to June Foliage Green lanceolate leaves Height 70 to 80cm (28 to 32in) Spread 45cm (18in) Position Full Sun to Part Shade Soil They grow well in any garden soil including clay. Germination 10 to 40 days Notes Often treated as Annual.