Plant Portrait - Ginkgo biloba, The Maidenhair Tree

Ginkgo is one of the most exciting plants we are growing, with a wide range of uses. This tall but narrow deciduous tree can reach a height of up to 30 metres with a spread of 9 metres. This species is the only surviving member of a family that was believed to be extinct until fairly recent times. It has probably remained virtually unchanged for at least 150 million years and might have been growing when the dinosaurs were roaming the earth. It is exceptional in having motile sperm and fertilization may not take place until after the seed has fallen from the tree. It belongs to a very ancient order and has affinities with tree ferns and cycads. The plant seems to be totally untroubled by pests and diseases and is believed to have evolved a resistance over its many millions of years of existence. I suppose that if it could survive the ravages of dinosaurs, then it is unlikely to be overly concerned about the attention of aphids or whatever.

A very easily grown plant, it succeeds in most soil types so long as they are well-drained, though it prefers a rather dry loam in a position sheltered from strong winds. Some of the best specimens in Britain are growing on soils over chalk or limestone. The plants flower and fruit more reliably after hot summers or when grown in a warm sunny position. Established plants are drought resistant, they also tolerate atmospheric pollution. They can grow in poor hard-packed soil, making them good candidates for street planting. Only the male forms are recommended for this, however, because the fruit from female plants has a nauseous smell.

The ginkgo is usually slow growing, averaging less than 30cm per year with growth taking place from late May to the end of August. Growth is also unpredictable, in some years trees may not put on any new growth whilst in others there may be 1 metre of growth. This variability does not seem to be connected to water or nutrient availability. Trees are probably long-lived in Britain, one of the original plantings (in 1758) is still growing and healthy at Kew Gardens.

Ginkgo is a popular food and medicinal crop in China, the plants are often cultivated for this purpose and are commonly grown in and around temples. The plants are either male or female, one male plant can pollinate up to 5 females. It takes up to 35 years from seed for plants to come into bearing. Prior to maturity the sexes can often be distinguished because female plants tend to have almost horizontal branches and deeply incised leaves whilst males have branches at a sharper angle to the trunk and their leaves are not so deeply lobed. Branches of male trees can be grafted onto female trees in order to fertilize them. When a branch from a female plant was grafted onto a male plant at Kew it fruited prolifically. We have often seen female trees with very good crops of fruit.

The seed can be eaten raw in small quantities, though it is best cooked when it can be used as a staple food. It has a soft and oily texture with a sweet flavour and the books say it tastes somewhat like a large pine nut. We ate some seeds for the first time in the autumn of 1996 and, when baked, they made very pleasant eating. Our verdict was that it tasted rather like a cross between potatoes and sweet chestnuts, and that we would love to be able to eat this food in quantity. The seed can also be boiled and used in soups, porridges etc. It is rich in niacin, is a good source of starch and protein, but is low in fats. These fats are mostly unsaturated or monounsaturated. When cooking the seed, it is best to leave them in their shells. These shells are very thin and it is a simple matter to crack them at the time of eating.

Some care has to be exercised if you want to eat the seed raw. It contains a mildly acrimonious principle, though this is entirely destroyed when the seed is cooked. This acrimonious principle is probably a substance called 4'-methoxypyridoxine, which can destroy vitamin B6 in the body. It is more toxic for children, but the raw nuts would have to be eaten regularly over a period of time for the negative effects to become apparent.

Ginkgo has a long history of medicinal use in traditional Chinese medicine, where the seed is most commonly used. When cooked it is used in the treatment of asthma, coughs with thick phlegm and urinary incontinence. The cooked seeds are also said to stabilize the production of sperm. The raw seed is said to have anticancer activity and also to be antivinous. It should be used with caution, however, due to the reports of toxicity.

Recent research into the plant has discovered a range of medicinally active compounds in the leaves and this has excited a lot of interest in the health-promoting potential of the plant. In particular, the leaves stimulate the blood circulation and have a tonic effect on the brain, reducing lethargy, improving memory and giving an improved sense of well-being. They have also been shown to be effective in improving peripheral arterial circulation and in treating hearing disorders such as tinnitus where these result from poor circulation or damage by free radicals. The leaves contain ginkgolides, these are compounds that are unknown in any other plant species. Ginkgolides inhibit allergic responses and so are of use in treating disorders such as asthma. Eye disorders and senility have also responded to treatment. The leaves are best harvested in the late summer or early autumn just before they begin to change colour. They are dried for later use.

The seed is best sown as soon as it is ripe in the autumn, though it can also be sown in late winter as long as it is not allowed to dry out. There is some disagreement as to whether the seed needs to be exposed to cold weather before it will germinate. In cases such as this we try to ensure that the seed experiences some cold weather, but is protected from the worst extremes of the weather. Sowing in a cold frame or unheated greenhouse usually works well, though make sure the seed is protected from mice, birds and squirrels. The books say that germination is usually good to fair, though we have tried sowing them on many occasions and have yet to get the seed to germinate. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for their first year. Plant them out into their permanent positions in the following spring and consider giving them some protection from winter cold for their first winter outdoors.

The seeds are marked by either two or three longitudinal ridges, it is said that those with two ridges produce female plants whilst those with three ridges produce male plants.

Ginkgo can also be propagated by cuttings, and this is a good way of ensuring that you get plants of known sex. Half-ripe wood about 15cm long can be taken during July or August. Put these in a frame, preferably with bottom heat, and make sure they are kept moist. They may not grow away in their first year but usually grow all right after that. Cuttings of mature wood of the current year's growth can also be used. Shoots about 15 - 30cm long are taken in December and placed in a fame. They should root in the spring.

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Readers Comments

Ginkgo biloba, The Maidenhair Tree

Peter Linder Tue Jan 30 15:19:07 2001

I don't believe you could tell a female ginkgo from a male one through looking at its leaves or on how many ridges the seeds have.

Ginkgo biloba, The Maidenhair Tree

Jo Sat Oct 20 21:59:57 2001

I've had seed from Chilterns this year and couldn't get any to germinate at all. If anyone has had any luck please tell me how you did it.

Jo

Ginkgo biloba, The Maidenhair Tree

Greg Aitken Sun Mar 3 16:45:06 2002

Prefers hot, continental summers for rapid growth. Not suitable for cold maritime areas. Roots will not penetrate compacted subsoil when loose topsoil is available. Success on compacted sand with no ammendments except surface mulch of tree chippings; tree became drought tolerant quickly under these conditions. Note that drainage was good.

Ginkgo biloba, The Maidenhair Tree

Fri Oct 18 20:03:27 2002

I've had luck getting them to germinate a number of different ways:

1. Put the whole seed in pots and bury the pots in the ground for the winter. Dig up the pots and let them germinate naturally in the spring.

2. Very lightly crack the seed coat and soak in water for a couple of hours. Follow same procedure as above.

3. Keep seed in refirgerator for the winter. Sow seeds in the spring.

4. Scuff seeds with sandpaper until only a slight hole is made where you can see the center of the seed. Soak seeds in water for 24 hours. Sow seeds in the fall following procedure # 1 or keep seeds in refrigerator for the winter and scuff, soak, and sow in the spring.

Each year I try a different method and the seeds have germinated every year. Many die after germination, however, usually due to a late frost. I get my seeds either from people selling them on Ebay - www.ebay.com or from whatcom seed co. - www.seedrack.com and I also understand a company called richters sells them in their herb catalogue. Hope this helps. Good luck!

Ginkgo biloba, The Maidenhair Tree

John Piccione Tue Sep 30 00:41:36 2003

While this tree does provide wonderful shade in summer, the smell of fall comes quickly with the stench of its matured fruit the last week of September.

I am very interested in knowing what can be done to prevent the growth of the fruit.

Ginkgo biloba, The Maidenhair Tree

Mike Tue Apr 13 21:42:41 2004

Read the Ginkgo Pages: www.xs4all.nl/~kwanten

It is the best Ginkgo Biloba Page of the world!!!! (And very helpful!)

Mike

Link: The Ginkgo Pages

Ginkgo biloba, The Maidenhair Tree

Daniel Carbonneau Fri Jul 29 2005

Rarexoticseeds: rare seeds in small packs. Supplier of seeds in small packages. Assortment includes trees suitable for bonsai, including baobab, carnivorous plants and a lot more exotic seeds. The site includes item descriptions, germination tips and images.

Ginkgo biloba, The Maidenhair Tree

Eric Nichols Fri Sep 16 2005

There is a dozen of them growing in my neighborhood Livermore CA Bay area Findley Ave. Only one closest to Madison Ave. is female and it is loaded with fruit. Im going to take some seeds to Hawaii. In Corvallis OR there are half a dozen on OSU campus 30th or 35 St. Maybe all female. Fertility problem?

Ginkgo biloba, The Maidenhair Tree

Julia Dowhaluk Wed Nov 16 2005

Hi, I have been collecting the seeds from the tree, as I have watched a lot of Korean people gathering them in the park. How do you eat the nut inside the shell? Is it o.k. to eat raw or how should it be eaten? Can you give me some advice? Thank you

Ginkgo biloba, The Maidenhair Tree

Sat Jul 22 2006

a question before asked how to defrentiate a male from a female plant or tree for ginko and i believe the trick is in the angle ofthe branches.

Ginkgo biloba, The Maidenhair Tree

Betsy Browder@earthlink.net Fri Sep 1 2006

I use the lazy-person's way of germinating ginkgo fruit and I have hundreds of seedlings the next early summer. I live in Zone 6, USA. When the fruit falls, I leave it under the tree to fertilize the tree. /frost In November, before cold comes, I cover the fruit with a thick blanket of straw, at least 4". I water it some during a bare winter; not if there is some snow cover. In the warmer 60 degrees, I thin the straw to 2" maximum. Then I start watering the straw, but not to a soggy point, every several days. I pull the straw all off when I see the fruit growing green leaves. Betsy, Northern New Jersey, USA

Ginkgo biloba, The Maidenhair Tree

Betsy Browder Fri Sep 1 2006

I use the lazy-person's way of germinating ginkgo fruit and I have hundreds of seedlings the next early summer. I live in Zone 6, USA. When the fruit falls, I leave it under the tree to fertilize the tree. In November, before cold comes, I cover the fruit with a thick blanket of straw, at least 4". I water it some during a bare winter; not if there is some snow cover. In the warmer 60 degrees, I thin the straw to 2" maximum. Then I start watering the straw, but not to a soggy point, every several days. I pull the straw all off when I see the fruit growing green leaves. Betsy, Northern New Jersey, USA

Ginkgo biloba, The Maidenhair Tree

Janice Wickerman Tue Sep 19 2006

Why do all the leaves fall off so quickly?

Ginkgo biloba, The Maidenhair Tree

David Hymers Mon Nov 6 2006

I picked up 4 seeds from trees growing roadside in Georgetown Washington D.C. in October 2004 and brought them home to Berkshire U.K. I had detailed instructions from a website which said to put them in the fridge over the winter, then cut into them with a file and plant them. Two germinated and are currently burgeoning; I kept them indoors last winter and the leaves did not fall until late December. This year I am leaving them out in pots and so far the leaves show no sign of falling.

Ginkgo biloba, The Maidenhair Tree

don thalheimer Mon Nov 13 2006

does anyone else eat the fruit and like it? any side effects?

Ginkgo biloba, The Maidenhair Tree

Steve Fri Nov 24 2006

How do you tell if the nuts from the female are sterile? I have a female tree and do not know where a male tree is. but there may be one less the 1/4 mile away or even closer.

Ginkgo biloba, The Maidenhair Tree

Ken Fern, Plants for a Future. Sun Nov 26 2006

If a tree produces seed then it is almost certain that there is a male tree somewhere in the vicinity that has fertilized it. Any seeds produced are likely to be fertile, but the only way of telling for sure is to sow them and see if they germinate. There are lots of tips on this page about doing this.

Ginkgo biloba, The Maidenhair Tree

Barry Fri Jan 26 2007

These actually don't produce fruit, the fleshy parts are actually seed coats. Anyway, they don't really need hot humid summers. There is an old specimen which looks fantastic growing at Colton hall in Monterey that has to be close to 40 feet tall and is gorgeous in look, especially when the leaves turn yellow. The fruit does smell, but I don't think it smells nearly as bad as some people say. The fruits can cause allergies in those sensitive to poison oak, sumac, or ivy, so be careful when handling seeds.

Ginkgo biloba, The Maidenhair Tree

kim baller Sun Feb 11 2007

I live in Portland, Oregon, USA, USDA zone 8. I've been propagating seeds of Ginko Biloba for almost 20 years. I collect seeds from several prolific seed-bearing trees in the area, put them in 4 in. pots in the Fall with ordinary garden soil and leave them outside all winter with no protection of any kind (we have wet winters). In the spring I usually have about 60% germination. I keep them in the 4 in. pots through the first summer and then repot them into one gallons. I give them away usually in their second summer. I've given away hundreds of plants.

Ginkgo biloba, The Maidenhair Tree

Danielle Fri Feb 23 2007

Planted about 4 seeds around last May. Soaked them overnight in a cup of water, then potted them, covering with a little less than an inch of dirt. They all grew nicely. Though, seeing as how this is Florida it's February and they're just starting to drop their leaves. The weather kept changing here from warm to cold so the leaves were yellow for a month and a half before they started falling last week. I hope to get a good amount of growth when they come out of dormancy for the spring so I can transplant them into the yard about this time next year. Trees planted in zone 9b, don't leave them outside on the first winter as frost will kill off a couple leaves on the plants (mainly the first little ones closest to the level of dirt in the pot).

Ginkgo biloba, The Maidenhair Tree

Paul B> Bray Tue Mar 20 2007

there is a specimen tree on the South east corner of Cary Quadrangle on Purdue University campus in West Lafayette, IN. As a student this female tree was fruitful each of the two years I resided on the third floor. As a student I was ready to chop it down, now in retropect it is a beautiful tree viewed from a distance and with open windows as opposed living up close and personal each fall.

Ginkgo biloba, The Maidenhair Tree

Sarah Morse Thu May 31 2007

Anyone willing to swap or sell some seeds? I used to live in Portland Oregon where ther are a number of mature trees downtown, I miss them, they are my favourite tree. Thanks, deltadeliquent@yahoo.com

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