Eric’s Pet Plant: Ginkgo
Over in Connecticut, our friend Eric at Yale’s Marsh Garden has lifted his eyes from his greenhouse’s travails and fastened them on the ginkgo trees. Herewith his overview of the ginkgo’s unique place in the plant kingdom, its fascinating history – and its worthiness in the garden.
Ginkgo biloba, the Maidenhair or Ginkgo
By Eric Larson
Our Plant for this week is showing its fall color, which makes it one of the stars of mid-November. Many trees and shrubs have already dropped their leaves, closing off the connections from leaf to stem in preparation for the long winter ahead. But Ginkgos and a few others hang in there, sometimes right into December. This is a problem for the homeowner who has to shovel early December snow on top of a load of wet leaves on the sidewalk. There are several notable aspects about Ginkgo that are worthy of comment here.
As many of you know, the plant kingdom is divided into sub-sections starting with the division, which is further sectioned into class, order, family, genus and finally species. There is only one member of Plantae, the plant kingdom, that has its very own family, order and class: Gingko biloba.
It is the only member of Ginkgoaceae, which is the only member of Ginkgoales, which is the only member of Ginkgopsida. This is partly because Ginkgo is an ancient relic of long-ago times, a survivor of more than time in fact. There is some indecision amongst plant taxonomists about the relationship of Ginkgo to other plants. Some place the class in the Spermatophyta division, while others insist that Pinophyta is more appropriate.
Because the seeds are not covered by an ovary wall as in the apple, it is morphologically consistent with inclusion as a gymnosperm. The seeds are composed of two sections, a softer outer section called the sarcotesta, and the tiny hard inner part called a sclerotesta. Ginkgos are dioecious, meaning there are males of the species and females of the species, distinct individuals who must each contribute to the sexual reproduction of their kind. In late autumn, you will wish there was no fruit if you live near a female. It is much preferred to be living near a male, although the fruits are considered important food crops in East Asia. More on that later.
Besides G. biloba, no other member of the order Ginkgoales exists outside of the fossil record since the Pleistocene. The relatives harken back to the Permian, dating back 270 million years. The relatives and even this species evolved during the Jurassic in an era before flowering plants, when ferns and cycads (Ginkgo’s closest living relative) predominated, forming a low somewhat sparse canopy. This is one reason why Ginkgo biloba is often referred to as a fossil plant.
Thought for the longest time to be extinct in the wild, several small areas of seemingly native stands were discovered in very distant parts of China – “ginkgo” comes from the Chinese word for the tree. (It was brought back to Europe in the 17th century by the German botanist Engelbert Kaempher,) After genetic study, these stands were found to be so similar as to suggest that they were planted from one batch of seedlings. It is thought that these patches were planted and preserved by Chinese monks over a period of more than a thousand years. Now that’s some environmental activism.
Growth Habit and History
Ginkgos are large trees, when given the right conditions. Growing in China up to 50 meters (around 150 feet), under cultivation they generally grow to around ninety to a hundred-and-ten feet, with a pretty narrow spread. They prefer full sun, a well drained but rich soil and adequate moisture.
But they are supreme survivors, and will do well in some very forbidding soils, climates and conditions. They are extremely pollution tolerant, disease and pest resistant and tolerant of restricted root zones, which makes them a good candidate for a street tree.
Not only that, as I mentioned earlier, they are a survivor of more than time. About 4000 feet from the hypocenter of the atomic bomb blast that leveled Hiroshima in 1945, a large Ginkgo tree lived outside of a temple. The shock wave and firestorm completely leveled that area and defoliated the tree, but it budded out the following spring and still lives today, without any major deformities. For this reason it is called ‘the bearer of hope.’
(By the way, the temple was re-built, and instead of taking down the tree as was suggested by some, they built around it, with steps on either side.)
Ginkgo is the national tree of China, with cultural and religious significance in Buddhism and Confucianism. Some cultivated specimens in Japan and China are over 1500 years old.
The nutlet is used in congee and other traditional Chinese dishes, such as the vegetarian dish Buddha’s Delight, served for special occasions such as weddings and the New Year. Getting to the nutlet can be a smelly chore, though. Anyone who has experienced the fruit of the tree knows that the olfactory presence is not the most appetizing aroma.
When my brother Jeffry attended Haverford College in the early 1960’s, there were two large female Ginkgos planted just outside what was then used as the dining hall. That’s one way to save on comestible costs for a horde of hungry young men.
Is it Medicinal?
The herbal/medicinal uses of Ginkgo are all debatable. Some studies have shown it to be effective in sharpening the memory and other studies have shown there is no advantage. Besides memory enhancement, Ginkgo has also been shown to be effective in delaying the onset of dementia, easing some of the symptoms of tinnitus, relieving fatigue and contributing to improvement in cognition.
As I always write, this is not an endorsement of herbal uses for this plant; I only attempt to report what it can or has been used for. Please consult an herbalist, your holistic health practitioner or other quack for help in diagnosing and prescribing cures for what ails ye. (Actually I firmly believe in holistic medicine, so please forgive my loose banter about the nature of that practice)
Disclaimer: The opinions and views expressed herein are the sole responsibility of the author. Yale University and Marsh Botanical Garden and Leslie Land are not responsible for the inane and sometimes off the chart craziness of this publication.
“The idea is to die young as late as possible.”