Ginkgo biloba, or Maidenhair Tree, is a deciduous, dioecious tree native to Se. China. In nature, the trees can reach about 120 feet (almost 40 m) tall. In containers, their size is easily controlled with root pruning and container size. They make excellent Bonsai subjects. Branches are stiff, with both elongate and spur shoots. Medium green leaves are alternate and fan shaped, divided in the middle with a cleft; venation is open dichotomous. The seeds yield an oil which can cause dermatitis in some people. Seeds are eaten in the Orient and are believed to help with memory loss. Their content includes massive enough vitamin E concentrations that people may overdose and develop bleeding gums. The fleshy aril looks a bit like a cocktail onion, but has the memorably pungent odor of butyric acid. Production of seeds is highly variable. The unusual appearance of the tree reflects that it is a living fossil and could accurately be regarded as the last living seed fern--a deciduous gymnosperm of fascinating form. Trees are hardy in the landscape in USDA zones 5-10. They are very easy to grow.
Blooming: The tree is dioecious, the male strobili are catkin-like, and female ovules are borne in pairs on a long peduncle, with only one maturing. The seed is white to translucent and fleshy in appearance to 2.5 inches (6.5 cm) across.
Culture: Ginkgo biloba do best in full sun to light shade. For our trees in the greenhouse, we keep them on the small side, about 2 feet (0.6 m) tall. We use a soil mix consisting of equal parts of peat, loam and sand with calcined clay added to increase drainage. This gives a very well drained soil mix. We water the plants on a daily basis and fertilize them once a month with a balanced fertilizer. The plants are kept in our cool room all year, and subjected to outside temperatures in the summer months. In the fall, water is somewhat restricted as the plants start to lose their leaves. At this time, the nighttime temperatures are dropped to 48°F (9°C) for the winter. During this period, plants are root pruned and new soil mix is added. Plants are watered very carefully after root pruning. Fertilizing will resume in spring after new growth starts.
Propagation: Ginkgo biloba is propagated from cuttings, layers and seed. Seed is best collected in October and care must be taken to clean the fleshy aril from the seed (this can be a very unpleasant task given the odor of butyric acid). The seed is allowed to warm stratify for 2 months and then cold stratify for 2 months before germinating.
Ginkgo biloba was featured as Plant of the Week May 16-22, 2008.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.