The Curious History of the Ginkgo

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Gingkos used as street trees, here just before the leaves fall in October.

Would you be surprised to learn that a tree you can grow in your garden is a living fossil that has existed, practically without changing, for over 270 million years, well before the age of the dinosaurs? Well, that’s the case of the ginkgo or maidenhair tree (Ginkgo biloba).

200 plus million years ago, ginkgos were found all over the globe, even in the Canadian Arctic, where fossils can still be found to this day. But scientists believed it had been extinct for millions of years… that is, until German botanist Engelbert Kaempfer rediscovered the so-called fossil tree, alive and well, in the gardens of a Japanese temple in 1692. The tree caused such a stir when it was first imported into France that it originally sold for 40 gold crowns, a fortune at the time. Interestingly, the first tree imported into Europe and planted in Montpellier, France, is still alive over 300 years later… and it’s still only an adolescent, as finkgos are particularly long-lived  Some specimens found in Asia are believed to be over 2,500 years old!

Curiouser and Curiouser

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The fruit grows from a spur on female trees only.

The ginkgo is an odd plant on all levels. Its method of propagation, for example, is extremely primitive among seed-bearing plants, only shared by its distant relatives, the cycads. First, the embryo grows exposed to the open air, without being enclosed in an ovary, placing the tree among the gymnosperms, along with conifers. The female tree (the ginkgo is dioecious) forms large yellow fruit, the size of a plum, which have not yet been pollinated at the time of their formation. Thus, if there are no male trees in the vicinity, the fruit will continue to mature without a fertile embryo, much as a hen is able to produce an egg without an embryo inside if there are no roosters in the hen house. Odder yet, sometimes fertilization takes place after the fruit has fallen from the tree! (I’m trying hard not to imagine a rooster attempting to do that with a hen’s egg!)

Oriental peoples have long harvested and eaten ginkgo fruits, both raw and cooked. In the West, we’re less enthusiastic about them, notably, because they smell like dog poop when they fall on the ground and start to rot. That’s why you’ll usually only find male ginkgo trees in nurseries, as males, of course, don’t produce fruit.

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The unique fishtail leaf of a ginkgo.

The ginkgo’s leaf is unique as well, shaped much like a fishtail, with two lobes. The shape is similar to that of the leaflet of a maidenhair fern (Adantium), giving the ginkgo the common name maidenhair tree. The leaves fall in autumn, often becoming a beautiful golden yellow before they drop, another surprising detail considering ginkgos are closely related to conifers which are, for the most part, evergreen.

Still Around

For a long time it was believed that the ginkgo was extinct in the wild and that it had been saved from total extinction by Buddhist monks centuries ago. However, in 1956, wild ginkgo stands were found in two small forests in Southwestern China, and recent DNA studies confirm that they have a genetic diversity much greater than that of cultivated ginkgos, indicating these truly are a wild populations, not just trees that escaped from culture.

Taking It Slow and Easy

A ginkgo will grow almost anywhere in temperate climates, from USDA hardiness zones 3 to 9 (AgCan zones 4 to 9). It is also very adaptable to a wide range of growing conditions, doing well in well-drained soils of almost any quality as long as they receive full sun. Their great tolerance of polluted air, compacted soils and road salt making them an excellent street tree and they are widely used for that purpose.

Although a ginkgo can reach 65 feet (20 m) in height, its growth can be very slow: at the northern limits of its range, it may only grow an inch or so (a few centimeters) a year. So buy a good-sized tree if you want to create an interesting effect during your lifetime! Generally, trees sold in nurseries are produced by grafting or cuttings and are all males.

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Dwarf Ginkgo biloba ‘Mariken’ grown grafted onto an upright trunk.

Besides the standard ginkgo, there are many cultivars (all of them male) found in nurseries. Some have a narrow upright habit (‘Princeton Sentry’, for example), others, such as ‘Troll’ and ‘Mariken’, are dwarf cultivars that can be grown as shrubs, and there even several cultivars with variegated foliage, such as ‘Majestic Butterfly ‘. Sometimes dwarf varieties are sold grafted onto the trunk of a standard ginkgo, giving a dwarf tree with a lollipop silhouette.

There is little need for pest control treatments with this tree: over its long history, it has outlived most of its enemies. There are few insects, diseases or animals that will attack a ginkgo (one reader has reported Japanese beetle damage, but apparently this is very rare). It can even survive intense radiation, as evidenced by ginkgo trees that were severely charred during the atomic bomb attack of Hiroshima in 1945 only to resprout afterwards. Six of them grow there still.

A Living Commemoration

Finally, I have a suggestion for you: ginkgo is the perfect tree to plant to celebrate the birth of a baby. With its long life, it will certainly still be around for the child’s 100th birthday. And what a great story the child will then be able tell his or her great-grandchildren!

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