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Gardening in the Rainy Zone.
Pronounced: GINGK-go bi-LOW-bah
Sunset zones: A3; 1-10, 12, 14-24.
USDA zones: 4-9.
Height: 100 feet (30 m).
Width: 25 feet (8 m).
Male flowers are 1-inch long catkins. Female flowers are 1 ½ to 2-inch long pedicels bearing 1 or 2 green ovules, followed by a tan to orange, 1 to 1 ½-inches long seed with a fleshy covering, shaped like a plum.
Bright green leaves turn a wonderful yellow in fall. Clusters of 3-5 or single leaves on long shoots. Alternate leaves are fan-shaped and 2 to 3-inches long and wide.
G. biloba prefers sandy, deep, moist soil, but will grow in almost any soil.
Sow seed in containers as soon as ripe in autumn.
Semi-ripe cuttings in summer.
Young nursery grown trees may not grow if they are pruned in summer. Prune in late winter to early spring to remove crossing branches or wayward shoots to maintain a healthy framework.
Pests and Diseases:
Although not commonly a problem, some fungal leaf spots may occur, which are not overly problematic for the tree. The trees are not bothered by insects or diseases.
Rainy Side Notes
Ginkgo biloba has a rich history surrounding it. In prehistoric times, the deciduous ginkgo grew around the world. It earns the name "survivor" after growing on this earth over 200 million years ago, when the tree was prolific around the world. It is possibly the oldest living seed plant in the world. It is thought that dinosaurs spread the seed and when they became extinct, the number of trees declined. In modern times, this living fossil is native to two small areas in China. Although no one is certain, the tree may be extinct in the wild. The maidenhair tree is long lived, some trees growing for 3,000 years. When we look at a ginkgo tree, we can imagine a link to prehistoric eras, long before mammals became prolific on this planet.
On August 6, 1945 in Hiroshima Japan, an atomic bomb exploded. A ginkgo tree standing next to a temple, 1.5 km away from the center of the explosion, survived the blast that destroyed the temple next to it. The temple was rebuilt with stairs that surround the surviving tree. An engraving on it says, "No more Hiroshima." Three other trees survived that were in close proximity to the atomic blast; they are still living too. The Japanese consider these trees "Bearers of Hope."
In 1784, William Hamilton in Pennsylvania first introduced the tree to the United States.
Related to conifers, Ginkgo's fan-shaped foliage resembles a maidenhair fern's leaves, which is where its common name, maidenhair tree came from. In spring, the leaves are bright green; in autumn, they turn golden and hang on the tree for a while. When the leaves finally fall, they do it quickly and cleanly, leaving a lovely carpet of gold on the ground.
Ginkgos transplant easily and grow quite well in the Pacific Northwest. Carefully choose plants that are not root bound in their pots. The trees tend to look lanky when young but as they mature, they come into their own. If you are choosing a male to plant, buy a named clone to be sure you receive the right one.
The name gingko comes from the Chinese word, ginkyo, meaning silver apricot, describing the seed from the tree. Biloba is Latin for two-lobed, describing the leaf that is fan-shaped and split in the middle.
The fruit of the maidenhair tree is produced only on the female tree and is excessively messy when it falls to the ground. When the outer flesh of the seed begins to rot, it is very smelly. If you like the tree but do not want the mess or the odor, plant a male tree only. Some cities around our nation planted rows of these beautiful trees along their streets without regard to the mess and rotting fragrance each year. I have heard complaints from people in these cities that have the male and female Ginkgos on their streets. When the fruit falls and begins to rot, it does not smell pleasant to be in close proximity of the trees. If you want fruit, you will need both a female and male tree. Interestingly the sperm that fertilizes the female flower are motile and need water to accomplish their task of fertilizing.
Medicinally*, ginkgo is used to treat cerebrovascular problems. The Chinese used the leaves for the last 2800 years for many ailments, and today they use it to strengthen the heart and lungs and to treat chilblains. Germany recently approved the use of ginkgo for treatment of Alzheimer's disease; although it does not cure the disease, it helps treat the symptoms. Both the Chinese and Japanese use the seeds for other medicinal and culinary purposes. Ginkgo biloba is used to help memory; I use it myself for this purpose.
Photographed at the Hulda Klager Lilac Garden in Southern Washington.
Fall leaves photographed at Savage Plants & Landscape in Kingston, Washington.