Ginkgo Trees — A Link to the Past and Good Trees for the Present

Ginkgo Trees — A Link to the Past and Good Trees for the Present

Marianne C. Ophardt
Washington State University Extension
Area Horticulture Specialist

There’s a lovely row of old ginkgo trees in the parking lot at the WSU Research and Extension Center in Prosser,WA.  They were planted there many years ago and have grown into very nice specimens.   However, it wasn’t long ago that some employees wanted to have the trees cut down.  The problem was that several of these ginkgo trees have turned out to be female fruit producing trees.  The awful smell of the over-ripe fruit is what caused some to want the trees’ removed.  This is truly a nose-pinching smell akin to dog manure or worse. Pee-yuu! 

Although the smelly fruit do present a distinctly unpleasant problem, those at the center who wanted to keep these old ginkgo trees prevailed... and the trees have remained unscathed.  I’m glad.  Ginkgos are a living link to the prehistoric past... having originated over two hundred million years ago.  Once common in North America and Europe, the ginkgos were wiped out during the ice age and disappeared from North America seven million years ago and from Europe three million years ago.  Ginkgos were thought to be extinct until 1691 when a German physician and botanist, Engelbert Kaempfer, found ginkgos growing in Japan.

Kaempfer may have found the “lost” tree, but it was Buddhist monks who most likely saved this living fossil from extinction.  From about 1100 AD, Buddhist monks in the mountains of south-east China cultivated ginkgo trees in the courtyards of their monasteries.  The ginkgo trees were valued for their medicinal uses, edible seeds, and perhaps their beauty.  In about 800 AD, the monks brought the ginkgo with them to Japan where many years later Kaempfer found it.

Kaempfer was in Japan for two years (1690-1692) on a mission for the East‑India Company. When he wrote about his discovery in 1712 he called ginkgo trees "Amoenitatum exoticarum". At some point he brought ginkgo seeds to Holland.  It’s believed that one of the first ginkgos to be “replanted” in Europe was at the Botanical Garden in Utrecht ... where it’s still growing today.  In 1754, a ginkgo was planted at Gordon, the English botanical school, and in1762 at Kew Botanical Gardens.

From England, Holland, and Japan the ginkgo was gradually reintroduced to Europe and North America.  In 1784 a ginkgo was planted in William Hamilton’s garden in Philadelphia.  It then took about a hundred years for the ginkgo to become a popular street tree in east coast cities.  It was made more popular when famous architect Frank Lloyd Wright picked it as his favorite tree.  It’s now found in landscapes and cities across our country.

Not only is the tree’s “lost and found” history quite interesting, it’s an extraordinary tree in other ways too.  Botanists relish the ginkgo.  What particularly excites botanists is that the ginkgo has sperm that have flagellae, making them mobile.  Among living seed plants the trait of flagellate sperm is only shared with cycads.  These swimming sperm are found inside the ginkgo pollen grains. 

Ginkgo trees are dioecious with separate male and female trees.  The pollen is moved from male to female trees by the wind.  The female tree is pollinated in the spring when a pollen grain lands on one of its ovules.  However, actual fertilization of the ovule by the sperm doesn’t happen until the fruit matures, drops from the tree, and the stinky, fleshy seed coat rots away. 

Ginkgo bilobas are the only living members of the Ginkgo family which once consisted of at least 18 members.  All these other family members were lost millions of years ago. Ginkgoes are felt to be the link between ferns and flowering seed bearing plants.  

Unlike many other plants that have evolved in nature, the ginkgo has remained basically unchanged, probably thanks to the long cultivation by Buddhist monks.  Fossilized leaf material from270 million years ago is very much like the Ginkgo biloba of today.  That’s why Darwin called it a “living fossil”.  Botanists consider it a living wonder because it could be the oldest living seed plant in the world.

Ginkgoes are favored as a landscape and urban tree.  It’s a tough and durable tree with few insect pest or disease problems.  It’s also very resistant to pollution. It’s a hardy tree that does best in climates with wet winter weather and hot summers.  It does quite well in our region. The trees in Prosser are an example of their suitability for this area.

The tree itself is not especially pretty when young, but it does have an interesting growth pattern. As a young tree, it’s pyramidal in shape with a strong central leader.  Branches along this main trunk are regular, ascending, and asymmetrical.  The interesting growth of the ginkgo is due to its branching pattern.  The tree develops a combination of long and short branches that grow at right angles to the trunk and larger branches.  Its irregular growth pattern is attributed to the tips of larger branches sometimes becoming slower growing, shorter type of branches and the shorter side shoots changing to the faster growing, larger branches. 

The ginkgo’s unique bright-green leaves are produced alternately along longer branches and clustered at the tips of shorter side shoots. They’re two-lobed (“biloba”), fan-shaped, leathery, and smooth.  The veins fan out from the base of the leaf and aren’t cross-connected by smaller veins.  In the fall, the leaves turn a bright golden yellow and all drop off almost overnight with the first sign of cold weather.                          

The tree eventually grows to a height of 50 to 90 feet tall and 30 to 40 feet wide with a thick trunk, 13 to 30 feet in diameter.  Male trees generally have more of a columnar form, where females will have a somewhat wider crown.  As the trees age, they develop a wonderful grey bark with deep furrows.

Ginkgoes are a very durable tree.  Proof of that durability was found in Japan in 1945 after the atomic bomb was dropped on Hiroshima.  Human life was lost, buildings were obliterated, and plants were scorched and killed... except some ginkgoes survived.  Several ginkgo trees around the epicenter of the blast on a temple-site survived and resprouted without any visible genetic deformation.  Amazingly, two of these surviving trees still grow in Hiroshima today and are considered “bearers of hope”.

Remember that stinky fruit I mentioned earlier?  They look like yellow cherries and drop from the trees just prior to leaf fall.  It’s the fleshy outer covering that smells.  Inside a woody nut can be found. These nuts are a special food delicacy in China and Japan.

Today’s use of ginkgo leaf extract in a variety of natural medicines stems from its use in traditional ancient Chinese medicine.   The Chinese have used it to help with a variety of ailments.

It’s believed that ginkgo trees can live up to 3,000 years or more!  Ginkgo trees are honored trees in Asia where they have been seen as symbols of changelessness, unity, love, and hope and even possessing special miracle powers

Garden Note: If you want to plant a ginkgo tree, you may want to get a male tree.  They don’t produce stinky fruit, just the female trees do. However, female trees won’t usually flower or fruit until they’re about 20 years old!