There is a ginkgo tree here at Landis, located on the right side of the driveway as you walk toward the Barn, just below the Van Loveland perennial borders. Its leaves are distinctly fan-shaped, with a split in the middle that divides the leaf into two lobes. Hence, the genus name biloba, which derives from the Latin “bi” (two, or double) and “loba” (leaf). The leaves are bright green during the summer and often turn – all at once – a stunning yellow in the fall.
The lineage of the ginkgo tree makes the dinosaur look like a recent event. The Ginkgo biloba is the last living representative of the order Ginkgoales, a group consisting of about 18 members that date back to the Triassic Period, 300 – 350 million years ago – long before the Himalayas even existed. During this time, there were no trees on the earth’s surface other than the ginkgo. But there were many ferns – and this might be a clue to the ginkgo’s origins.
During the heyday of the dinosaurs, the Jurassic period of around 213 million years ago, the ginkgos dominated the earth. During the Cretaceous Period, 144 million years ago, perhaps as many as 15 ginkgo species were common and widespread in North America, Europe, and Asia. These trees began to decline about 65 million years ago, possibly as a result of the extinction of the dinosaurs who were important dispersers of its large seeds. Due to geological cataclysms, only a single species remained, Ginkgo diantoides, identical to the modern Ginkgo biloba. Ginkgos, the oldest living seed plants on earth, are considered to be one of the wonders of the world.
Like ferns and conifers, ginkgos are gymnosperms that don’t produce ripened fruit; their seeds are protected by a fleshy coat. The majority of gymnosperms have both sexes on the same plant, but the ginkgo is dioecious, with separate male and female trees. The flowers are inconspicuous, taking about 20 to 30 years to appear. The female produces numerous ovules that resemble cherries when formed. The males produce pollen cones which resemble catkins. Pollen is distributed by the wind. When the ovules are pollinated, they develop into yellowish, plum-like seeds about an inch long, consisting of one large nut within a fleshy cover.
If considering a ginkgo for your yard, be advised it may live longer than 400 years. It’s usually pyramidical shaped when young but spreads in old age, exhibiting large branches and a picturesque silhouette. Ginkgos are relatively fast growing, attaining a height of 100 feet and a spread of 30 – 40 feet. They prefer full sun to partial shade and moist, deep, well drained soils, but are extremely adaptable. They can survive in poor, compacted soils, various soil pHs, heat, drought, salt, and air pollution. The female ginkgo produces a foul-smelling fruit so landscapers recommend planting only male plants. But despite the odor, the fruit contains an edible nut used in Asian cooking.
The ginkgo’s ancient beginnings give it a unique advantage. It evolved before any leaf-eating insect, so insects that mutilate the leaves of other trees won’t touch a ginkgo leaf. It is also resistant to disease, fungi – and even radiation. On September 1945, after the atomic bomb was dropped on Hiroshima on August 6th, trees and plants near the epicenter of the blast were examined. A ginkgo that grew near a temple about 1,000 meters away from the epicenter appeared to be the only tree that survived and was the first tree to bud out without any deformities. That tree is alive today. Thus the ginkgo is considered to be a “bearer of hope.”
Volume 38 , Number 2