Maiden Hair Tree

Family: Ginkoaceae (Ginko family)
Genus: Ginko
Species: biloba

SteviaI’m going to take a few liberties this month. I don’t usually write about trees in these columns, particularly deciduous trees, especially the tall ones used for public landscaping, commonly called “street trees.” These articles are after all for home gardeners. But recently while looking up the spelling of “loathe” in the dictionary, I noticed “living fossil” one column over. Hmmm. Anyone who’s ever had any contact with teenagers knows that term well. I read the definition--an organism that has remained essentially unchanged from earlier geologic times and whose close relatives are usually extinct. The ginkgo biloba tree was given as an example. That caught my attention. An ancient survivor, the only one left of its kind!

Now, my history with Gingko biloba is uneven at best. When I set out to learn about plants, I started from the ground up, so to speak, and worked my way through annuals from ageratums to zinnias. Then I moved on to herbaceous perennials, took one side path to bulbs and another through ornamental grasses and landed lately at dwarf conifers. I know not very much about forest trees, or trees that grow along boulevards in cities or stand tall in the open countryside. Beyond Douglas firs and redwoods and red cedars and mountain hemlocks--with their little bent-over tops--and perhaps Ponderosa pines, I was lost. No one can live in our part of the country without knowing those. But once I casually referred to a Larix laracina--a tamarack--as a juniper. I was standing next to a wise Western naturalist at the time and he set me straight quick, after flinching as if I’d called an eagle a crow.

Two things about unfamiliar big trees seemed true to me then: Larix was noteworthy as a deciduous conifer and Ginkgo biloba--also a deciduous conifer--was truly an unpleasant tree. The first remains true, but I was really off base on the other. I’d walked on sidewalks dodging the squishy, bad-smelling fruit that dropped from the branches of ginkgo trees and wondered why anyone would plant such things anywhere close to where people congregate.

But after my dictionary discovery I decided to learn a little more about this tree, given its status as a lone survivor. And as I’ve found to be true time after time, once I gather some information about something I don’t think I like, my opinion is likely to change. Now I respect the gingko’s ancient heritage and even understand about those squishy fruit. The mess isn’t the fault of the tree, but of the people who chose to plant females rather than males.

It’s true there’s only one species--biloba--of the genus Ginkgo left on earth. And the tree is extinct in the wild. It’s been here for 200 million years in the same form we see it today but now survives only in cultivation, according to the Museum of Paleontology at the University of California, Berkeley. It’s still with us due to the efforts of “the Chinese priest classes” who grew it alongside their temples for centuries. “Some speculate that Ginkgo biloba’s decline in the wild may be related to the extinction of a seed disperser during the Pleistocene extinctions. Ginkgo seeds are difficult to germinate, which some have suggested may be related to the requirement that they pass through the gut during dispersal. However, such a scenario is difficult if not impossible to evaluate scientifically.” There is some evidence that the gut in question was provided by a raccoon.

No need to dwell further on that theory, just to add that today the ginkgo doesn’t naturalize where it’s grown. However, it has managed to recapture “much of its ancient biogeographic range because it is an excellent ‘city tree’ that grows well throughout the mid latitudes today.” It is an ideal landscape tree with many fine attributes. It demands nothing more than a sheltered place in the sun and soil that drains well. It’s not fussy about care. It’s cold hardy, not bothered by pests or diseases, and resistant to oak root fungus. Only female trees drop those fruits that make sidewalks slippery. Male gingkoes, readily available in the marketplace and clearly marked, don’t make messes at all.

And its suitability for home gardens? The species trees grow to at least fifty feet. Because their leaves and form are so beautiful, however, plant breeders have gone to work and now several very attractive, slow-growing dwarf forms are available, some with deep-green leaves and some with leaves tipped in gold. Be on the lookout for G. biloba ‘Mariken’, cultivated from a witches’ broom found on a species gingko. Or ‘Jade Butterflies’, very small, with its leaves in tight clusters. There may be only one species of Gingko, but there are many cultivars. If you want something new in your home landscape this year, you may want to check some of them out.

Oh, and it seems to me I’ve heard rumors that claims have been made about the health benefits of potions made from parts of gingko trees. But for the life of me, I can’t remember what they might be.

Image courtesy OSU Landscape Plants Database