One of the most interesting trees that can locally be grown is a ginkgo tree.
It was called a "living fossil" by Darwin because it is basically the same tree found in fossils from more than 200 million years ago. Most other plants were wiped out by drastic climate change and the ice age. The ginkgo tree that we know today, Ginkgo biloba, has survived with few evolutionary changes for at least 56 million years.
The ginkgo tree grew in America until the ice age about 7 million years ago. The only place in the world where they survived was in China, preserved possibly by Chinese monks and by natural geographic features.
Scientists believe the tree has been cultivated in China for 1,000 years, making its way out of China into Japan and Korea in the 14th or 15th century. In Asian cultures, it is a revered symbol of strength and longevity. A member of the Dutch East India Company introduced the ginkgo to the West in 1692.
The tree is unique. It has no close or distant relatives. The fan-shaped leaves are distinctly different from other trees, with a notch at the top and raised parallel veins. It is dioecious, meaning that there are separate male and female trees, with only the female producing a small plum-shaped fruit.
The fruit is one objectionable drawback. The nut inside is considered an Asian delicacy and served for special occasions. However, the fleshy part of the fruit stinks, many likening it to the smell of dog manure, and it could take 20 years for a female tree to produce fruit. Reputable nurseries only sell male ginkgos.
Some gardeners like the ginkgo for its status as a living fossil. Others like it for its unique form and leaves. As a young tree, the ginkgo has a columnar growth habit, eventually spreading out and developing an irregular oval shape. It takes a long time to reach its full potential of 70 to 80 feet tall. In the fall, the leaves turn a brilliant yellow and flutter to the ground seemingly overnight.
Ginkgo grows best in well-drained moist, sandy soils, but is tolerant to stressful conditions, such as heat, drought, compacted or alkaline soil. It is a long-living tree that is resistant to storm damage. Better yet, it has no significant pest or disease problems and is winter hardy.
The are numerous ginkgo available, including Autumn Gold that only grows 50 feet tall and has a broader, rounder crown; Jade Butterfly, which is a slow-growing dwarf half the size of the species; Pendula, with a weeping habit; and Princeton Sentry, with a narrower columnar form and growing 60 feet tall.
-- Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.