Gardening questions vary throughout the year and will sometimes depend on the weather. Over the holidays, people sent photos and emails to ask about the name of plants in their landscape, why their petunias are dying, and the identification of new growth from their orchid.
One plant photo sent in for identification was of Jatropha integerrima, also referred to as peregrina, Spicy Jatropha or firecracker. This tropical plant is more common in zones 10B through 11, but because of our mild winters for the last few years, it is becoming more common in our area.
Peregrina is an attractive multi-trunked evergreen shrub that can reach 15 feet tall with a matching spread. Dark green glossy leaves are variable in shape and may be oval to lobed. What really makes this plant an instant success is the flowers that occur almost year-round. One-inch-wide red flowers occur in clusters and are held upright above the leaves that serve as magnets to hummingbirds, butterflies and bees. Seed capsules follow, which contain several smooth speckled seeds that are toxic, so be sure to keep this plant away from small children.
Peregrina flowers best in full sun, but will grow in partial shade. Plants will not tolerate poorly drained soils, but otherwise adapt to most soil types. Peregrina is native to the West Indies and Cuba so will suffer damage during a frost or hard freeze. Consider using peregrina as an accent plant or a backdrop in a flower bed plus they work great in containers making it easy to move when there is a freeze. If they get too large, they respond well to pruning. There is also a Compacta variety, which tops out at 4 to 6 feet tall.
Another local gardener shared photos of small blooming plants in her landscape. The plants are lawn orchid or soldiers orchid, Zeuxine strateumatica, which typically bloom at the onset of winter. They were brought into the U.S. in the 1930s from Asia and are considered naturalized in the southeastern United States and Hawaii.
Lawn orchids emerge for about a three-week period and then are gone for the rest of the year. Plants are dark green in the shade or pinkish-buff in the sun and mature at 4 to 5 inches tall. Leaves are arranged in a spiral around plant stems. Showy small white flowers with a yellow labellum occur in terminal spikes atop stems.
Due to weather conditions, some local gardeners are having problems with their petunias. Based on the photo, the plants were dying back, and there was an obvious white cottony mass on affected leaves. As it turns out, petunias are susceptible to a fungus referred to as white mold, Sclerotinia sclerotiorum, which is active in cool moist weather. Although the days were warm, night temperatures dropped causing a heavy dew to form on plants. The affected plants are in the wave series, which have a tight prostrate growth habit that hugs the ground making them more susceptible to this disease.
Symptoms include spots that are water-soaked near the base of plants and stems become tan in color. As the disease progresses, white cotton-like growth (mycelium) appears on the stem, and stems may become hollow. Hard black sclerotia will develop in the white growth or hollow stems, which serves as a fruiting structure that may survive for several years. Lower leaves of the plant die, and the upper growth will wilt and die-back. Overall the plant appears to be water-soaked and just melts out.
Because the disease is difficult to control, the best thing to do is to remove and destroy infected plants before the sclerotia develop. Avoid overhead irrigation and rotate with plants that are less susceptible to the disease like pansy and alyssum. Other hosts for this disease are legumes, sunflowers, most vegetables and many flowering annuals.
Another gardener mailed photos of her Phalaenopsis orchid in hopes that it was forming a flower spike. The plant is a year old and has not bloomed and her patience was wearing thin. The new growth turned out to be a new root that was growing upright, which is difficult to distinguish from a new flower spike. However, if you look carefully, the root was smooth with a greenish tip whereas the flower raceme is not smooth and begins to show signs of flowers developing along the stalk.
Terry Brite DelValle is a horticulture extension agent with the Duval County Extension Service and the University of Florida/IFAS.