Ginkgo trees (Ginkgo bilboa), also known as maidenhair trees, are most commonly grown in the United States as ornamental trees. They are suitable for U.S. Department of Agriculture plant hardiness zones 3 through 8. Considered an ancient tree -- ginkgo trees may have lived on Earth upwards of 150 million years ago and are the only surviving member in its family. It is not known to live naturally in the wild. Ginkgo trees are most easily identified by their leaves, fruit and height.
A deciduous conifer, ginkgo trees are not native to the States. However, they are not considered an invasive species. The tree is dioecious, meaning there are male and female trees, though males are typically planted in the U.S. Mature trees can reach upwards of 100 feet. The tree is taller than it is wide, with an average width of up to 60 feet and the females are wider than males. It has a rounded and open crown and the tree's growth rate is slow to moderate. The gray bark forms furrows as the tree ages. Ginkgos are most commonly grown as a shade or street tree. Despite the showy, drooping thorn-covered branches, the tree is hardy and resistant to breakage, pollution and salty conditions.
About the Leaves and Flowers
Ginkgos lose their leaves come winter, after they turn from green to a brilliantly colored yellow in the fall. The color is short-lived because the foliage drops quickly. The leaves of the tree are often what distinguish it. With two-lobes and a leathery texture, they have veins that run almost parallel across the entire fan-shaped leaf. The leaves grow in an alternate pattern, and are 2 to 4 inches long. During the spring, ginkgos will also produce unremarkable pale green flowers.
About the Fruit and Seeds
The roasted seed pits produced by female ginkgo trees is considered a delicacy in Asia, though the seeds do have toxic properties and large quantities should not be consumed. The seeds, oval shaped and roughly 1 to 3 inches long, fall to the ground in autumn. The seeds are covered with a fleshy outer coating that splits open when the seeds fall, releasing an unpleasant odor that is said to resemble vomit. The flesh also often splatters, creating a mess. It can take upwards of 20 years or more before a ginkgo tree produces fruit.
Growing Ginkgo Trees
Ginkgo trees are easy to grow, tolerating a wide range of soils, including clay and sand. However, they prefer well-draining soil and are very drought tolerant. Ginkgo trees do well in full or partial sun, as well as partial shade. The roots of the tree are not problematic for pipes, foundations or sidewalks, and it is generally free of pests and other diseases. To avoid the potential messiness of the falling seeds, plant only male cultivars such as "Autumn Gold," "Fastigiata," "Lakeview" or "Princeton Sentry," suggests the University of Florida IFAS Extension. There is no way to tell if a seedling is male or female until it produces seeds.