Ginkgo is the world’s most ancient tree and the only surviving member of its genus. Native to China, where it has long been considered a sacred species, the ginkgo was first planted in the United States in 1784 on an estate near Philadelphia. The tree is rarely found in the wild today, and scientists debate whether even these small stands are truly wild.
The name ginkgo comes from the Japanese gin (silver) and kyo (apricot). Because the plant is believed to have positive effects on memory, brain function, and circulation, it has been called the “antiaging” herb and is one of the best-selling herbal supplements in the United States. Ginkgo is grown commercially in the United States, France, China, and Japan.
Common Names: Ginkgo, Maidenhair Tree
Description: Large deciduous tree, up to 100 feet or taller; fan-shaped leaves are deeply notched to form two lobes; females bear yellow-orange, odoriferous fruits
Hardiness: To Zone 3
Flowering: On separate male and female trees, appearing in March and April
Parts Used: Leaves and seeds
Range/Habitat: Native to China; cultivated in Asia, France, and southeastern United States
Although raw ginkgo seeds can be toxic, the cooked seeds (called nuts) are considered a delicacy in China. To obtain ginkgo nuts, remove the fruit pulp, then crack open the nuts’ outer shell. (Wear gloves when you do this; the fruits are notoriously foul-smelling, and handling the nuts can cause contact dermatitis in some people.) In China, ginkgo nuts are added to vegetable and rice dishes and are served at weddings and other special occasions. In Japan, the nuts are eaten after meals to aid digestion.
Ginkgo seeds have been used as medicine in Asia for thousands of years. The Chinese eat cooked ginkgo nuts to increase strength and sexual energy and to restore hearing loss. Boiled as a tea, the nuts are used to treat coughs, asthma, allergies, and wheezing.
Modern herbalists primarily use ginkgo leaves. The leaves have antioxidant properties and contain flavonoids (called ginkgo flavone glycosides) and terpenoids (called ginkgolide and bilobalide) that could help improve blood flow to the extremities and to the brain, eyes, and ears, particularly in the elderly. Ginkgo supplements have been researched for the treatment of tinnitus, high blood pressure, and concentration and memory problems, as well as for slowing the progression of Alzheimer’s disease. While there are clinical studies that showed promise in this area, several recent studies have failed to substantiate the supplements’ effectiveness for these conditions. Because of the plant’s ability to dilate blood vessels, the herb is also used to treat intermittent claudication (intense cramping in the calf muscles).
Ginkgo leaf extract, rich in flavonoids and di-terpenes, is used widely in cosmetics, shampoos, and skin creams. The hardy, long-lived trees are often planted along city streets. They’re also a favorite subject for bonsai.
How to grow it
Ginkgos are commonly grown for their beauty and ability to withstand cold temperatures, pollution, insect pests, and diseases. Plant ginkgo in full sun and well-drained, fertile soil. Most home gardeners plant only male trees grafted from other males to avoid the smelly fruits borne by females. If you wish to harvest ginkgo nuts, however, you’ll need to plant both male and female trees. Prune young trees to a central leader. For making an extract, harvest the leaves in fall and then them.
An Ancient Memory
Ginkgo seeds — found inside the orange-yellow fruits — are highly valued in the cuisines of China, Korea, and Japan. While some cities no longer plant female ginkgo trees because of the fruits’ terrible odor, caused by butanoic acid, the stately ginkgo certainly deserves a place in modern cities.
The genus Ginkgo is known from Chinese paleobotanical specimens more than 200 million years old. The renowned botanist Carl Linnaeus named the plant in 1771, basing the genus name Ginkgo on the plant’s Japanese common name and the species name biloba on the two lobes found on each leaf. Ginkgo arrived in the United States through the botanist and plant explorer André Michaux in the late 1700s. Today, this ancient Chinese medicine is being studied extensively to evaluate its efficacy in the treatment of conditions ranging from lung problems to memory loss. The next time you see a ginkgo, remember that its ancestors have been around for as long as Mother Nature can remember.