Can male ginkgo trees have fruit?

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Question Can male ginkgo trees have fruit?

Answer Ginkgo is a dioecious tree, meaning each tree is either male or female. Female trees have fruit which contain seeds (sometimes called nuts). Acids surrounding the seeds cause ginkgo fruit to produce a putrid smell. Butyric and hexanoic acids are the primary stinky culprits. Butyric acid is a natural fatty acid. It can be synthesized and is commonly used to manufacture plastics. Butyric acid is found in animal generated products like butter or human sweat. As bacteria free the acid, it generates a distinctive scent. Hexanoic acid has an unpleasant odor like butyric acid. It is also harmful to aquatic systems. Ginkgo seeds should not be allowed to fall into or collect in ponds, streams or pools.

The combination of butyric and hexanoic acid produces a smell similar to canine feces, rancid butter, vomit and/or rotting flesh. This wonderful aroma was created 270 million years ago during the Permian period. Ginkgoes flourished during the time of the dinosaurs (Jurassic 213 million years ago). The foul odor of their fruit attracted reptilian carnivores to consume, scarify and transport seeds to new locations. While t-rex no longer slobbers on ginkgo branches, modern day dinosaurs (opossums, raccoons, skunks and large fruit eating birds) continue to eat, transfer and prepare ginkgo seeds for planting.

Possums and coons obviously have a different idea of what a Thanksgiving meal should smell like. The smell of ginkgo fruit typically triggers a gag reflex in the average person. No matter how much respect we have for the eldest of the arboreal realm, we will not tolerate stinky ginkgo fruit on our lawns and sidewalks.

Luckily, we have male ginkgoes. Male trees are not supposed to have fruit any more than men are supposed to have babies. Unfortunately, ginkgoes didn’t get to be the oldest tree in the woods by being inflexible. Approximately one in every 200 male trees will be monoecious. This means it will have both male and female flowers on the same tree. This also means it will produce some stinky fruit. Reputable nurseries sell varieties of male ginkgo trees. These varieties are grafted in order to eliminate genetic variation. In other words, these male trees will not develop the urge to wear dresses or have female flowers.

At this time, there isn’t any way to tell whether a seedling ginkgo is a male or female. Even DNA tests are inaccurate. The average female tree is about 20 years old before it begins fruit production. Some female trees have waited 40 to 45 years before producing fruit. If you get your hands on a seedling that was processed and planted by a skunk, it’ll be a while before you’ll know whether the tree will smell like a skunk.

For more info on ginkgo trees, visit http://hcs.osu.edu/hcs/TMI/Plantlist/gi_iloba.html If you don’t have internet access then call me at 910-893-7533 or email me at gpierce@harnett.org

As a Southerner, I don’t mind the smell of chitlins. For whatever reason, folks in San Francisco rather smell ginkgo nuts (http://www.naturesbalanceacupuncture.com/pdf/recipes/Gingko_Nut_Porridge.pdf).

Gary L. Pierce

Horticulture Extension Agent

Harnett County