I have been waiting weeks for my favorite moment in fall. It’s almost here! My ginkgo is turning golden and is getting ready to drop its leaves!
It might not be an exciting prospect for some people but the fall leaf drop of Ginkgo biloba is something I find amazing and wonderful. Before I get into why, let me tell you about this fantastic tree.
Ginkgo biloba is a living fossil—fossils of Ginkgo biloba date back 270 million years, predating even the dinosaurs. This tree is truly durable and long lasting. They make excellent street trees, tolerating restricted soil space and pollution. Several even managed to survive the detonation of the atomic bomb over Hiroshima, Japan!
Though ginkgo tree habits tend to vary between cultivars, they can grow anywhere from 50-100 feet high and 30-40 feet in diameter. When left to grow naturally, these trees will grow slowly, but growth can be accelerated with the help of fertilizer and watering. Young ginkgoes can often be very open and awkward-looking when left unpruned, and this is clearly visible with some street trees. Their habit, however, will improve with age as these young, long branches will become massive and reminiscent of old oaks over time.
Ginkgoes can be male or female, and identification is easiest at this time of year. Your nose can tell you if a ginkgo is male or female before you even see it. The female typically produces an abundance of fruit with a bad odor. In fact, the University of Illinois has a female ginkgo tree near the center of campus where students frequently walk, and it is not uncommon to see people checking their shoes, thinking they “stepped in something.” This fruit frequently makes a mess on lawns, paths, and sidewalks. That is why males are usually preferred for landscapes.
In spite of the fruit odor, and beyond their ornamental value, some research suggests that the leaves can be used to improve memory and concentration. The leaves also increase the body’s production of norepinephrine, which can increase heart rate. The seeds of the female tree can also be used in cooking and are sometimes considered an aphrodisiac. If you are interested in picking the fruit, however, make sure to pick fallen fruit and wear gloves, because some people will have an allergic reaction from contact with the fleshy coating.
My favorite thing about ginkgoes, however, is their dramatic fall color and leaf drop. The leaves of ginkgo turn a beautiful golden yellow that rivals the fall color of birches. Beyond their fall color, the real drama happens after the first few golden leaves fall. After this, you can expect the rest to fall within the next 48-72 hours, carpeting the ground beneath it in golden yellow leaves.
If you’re thinking about growing a ginkgo, it is important to always consult with a nursery about the varieties they have, and the gender of the trees. Buying an unnamed cultivar grown from seed is a big risk if you don’t want to be cleaning up the fruit later. (It takes 20-50 years for a ginkgo to produce fruit, so you may suffer the consequences if you don’t attend to the details when you make your initial purchase.)
I hope you can find your way to the Garden and check out all our wonderful ginkgoes!
©2013 Chicago Botanic Garden and my.chicagobotanic.org