Friday, November 06, 2009
Ginkgo is one of the oldest surviving trees and has been found in the fossil records more than 270 million years ago.
Ginkgo biloba, a dozen of which are planted around the Arboretum, are reputed to be long-lived and grow best in well-watered and well-drained soils. The Ginkgo is believed to be extinct in the wild, but cultivated specimens were found in China, preserved by monks, and from them re-popularized around the world. The species was first brought into the United States by William Hamilton in 1784 for his Philadelphia garden. Frank Lloyd Wright popularized the tree and thus it has made its way across North America.
The ginkgo is dioecious - meaning reproductive organs are found on separate trees (like the persimmon) - the males on one, the females the other. The fruit, found only on female plants, when fertilized, becomes an oval, tan-orange globe that, unfortunately, has a most 'disagreeble' odor . I won't go into the comparisons of its scent, but the smell is so bad that many female trees were removed from city streets. The male ginkgoes do not produce a fruit and thus are those most often planted in the landscape.
Ginkgoes are virtually pest and disease free, slow growing, and can reach heights of 75 feet. They grow in US hardiness zones 3-8A with a spread of 50-60 feet when mature. Their fan-shaped leaves are unique and turn one of the prettiest yellows during the fall season. The ones I've painted have come from the Arboretum's trees. Two of the grouping are completely yellow, while the rest - just barely losing their green!
Ginkgo leaf extract has been used to treat a variety of ailments and conditions, including asthma, bronchitis, fatigue, and tinnitus (ringing or roaring sounds in the ears). Extracts have also been used to improve memory and to treat Alzeimer's disease.