Sometimes called the living fossil tree, Ginkgo biloba is the sole remaining member of the Ginkgoaceae family. It dates back an estimated 150-200 million years to the Triassic period but is no longer found existing in the wild. After being considered extinct, it was rediscovered in the 17th century by Buddhist monks and subsequently introduced to Europe in the 18th century.
Since its reappearance, Gingko biloba has gone on to become a popular ornamental tree in parks and gardens throughout the world, including in Southern California, where it grows well everywhere but the desert regions (Sunset Zones 11 and 13). Frank Lloyd Wright even favored this tree for the landscape designs associated with his architecture. It functions well as a shade tree or as a single ornamental specimen. It is also considered highly desirable for bonsai training and at least half a dozen cultivars have been created for this purpose.
Also known as the maidenhair tree, Ginkgo biloba’s leaves resemble those of the maidenhair fern. Not only are there medicinal properties attributed to its leaves, they are unique and attractive in their own right. The fan-shaped, bilobed foliage is bright green during the growing season, all at once turning golden-yellow in the fall. The leaves are held by especially long petioles and, with their fanlike shape, easily flutter in the lightest of breezes. The golden leaves of autumn sometimes seem to gleam in the sunlight and they remain on the tree until well into the season when they finally fall to create a golden mat below.
Ginkgo biloba is a picturesque tree that is columnar and sometimes gawky when young but takes on a more spreading and generally well-proportioned look as it matures. It is extremely long-lived, even as much as 500-600 years according to some horticultural observers. In this region it generally grows a foot per year, though up to three feet per year is possible under ideal conditions. In Southern California it can reach 75-80 feet in height, but mature trees here are more likely to be 40-50 feet in height and 25-30 feet wide. As it matures, it often loses its central leader, which is replaced by several trunks that continue the tree’s vertical growth.
An adaptable tree, Ginkgo biloba will do fine with either full or partial sun, though full sun is more likely to produce the best fall color. It prefers loose, well-drained soil, but it tolerates dry, compacted soil as well as extremes of heat and cold. Urban air pollution does not seem to disturb it and it is virtually immune to pests and diseases. It is also resistant to oak root fungus.
Ginkgo biloba is dioecious, meaning the male and female flowers are borne on separate trees. Propagation is either by seed or by cuttings from cultivars grafted onto seedling rootstock. With propagation from seed, however, it often is impossible to determine the tree’s gender until it is at least 20 years old, at which time it finally starts to bloom. A major drawback of female trees is the truly wretched odor produced in the early fall when the fruit drops and starts to decay. Not only does the fruit smell rank, it also turns into a slimy mess on the ground below, and the rotting fruit reportedly damages paint. For these reasons, it’s important to make sure you plant a male tree. Since there is no reliable way to differentiate female from male seeds, trees propagated from seed are best planted in remote areas.
The most popular Gingko biloba cultivars that are reliably male include the following: “Autumn Gold” – dependably golden-yellow in autumn with a broad, upright growth; “Princeton Male” – tall, very columnar form; “Fairmount” – fast growing and pyramidal with a straight main stem; “Pendula” – rounded, weeping habit; and “Variegata” – yellow and green variegated leaves.
It is important to select trees for planting that have not become root bound in the container. In addition, the newly planted young tree should be staked to keep the stem growing straight and erect. Young trees tend to be a bit brittle, but their wood strengthens with maturity.
Related article: A to Z plant guide: How to grow everything in Southern California
Contact the writer: The University of California Cooperative Extension Master Gardeners, http://www.uccemg.com are certified horticultural volunteers dedicated to relating gardening information to the public. For answers to horticularal questions, call our hotline at 714-708-1646 or send email to ucmastergardeners@yahoo.com.
