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The tree

Classification

During the time of the dinosaurs seed plants (spermatophytes) were well developed and were the most dominant vegetation on earth, especially the lush seed ferns, conifers and palmlike cycads. These primitive seed plants are called gymnosperms (meaning "naked seeds") because their seeds are not enclosed in a ripened fruit but are protected by cones or by a fleshy seed coat.

Most gymnosperms (and flowering plants) have both sexes on the same plant, but the Ginkgo is a dioecious gymnosperm, male and female are separate trees, its seeds have a fleshy outer layer.  The Ginkgo and the cycads are the only living seed-producing plants that have motile or free swimming sperm (more info here). In earlier classification systems the Ginkgo tree was placed in the class Coniferopsida, because it is thought to be more related to conifers than to any other gymnosperm, but the two groups appear to have evolved independently.  Although the Ginkgo is more like a conifer than a deciduous broadleaf tree it is neither, it has a unique position. Recent research suggests a much closer relationship to the cycads than to the conifers.

about 2,500 years old Ginkgo Queen in China photo Wei Gong

You can distuinguish a Ginkgo from other gymnosperms by its fan shaped and bilobed leaves. All Ginkgo trees have a relatively primitive vascular system. The veins continuously divide into two's. This vein pattern (dichotomous venation) is unique to the Ginkgo.

Because of its unique position botanists found it difficult to classify the Ginkgo. Therefore the Ginkgo has been placed in a separate group in recent years, the division (phylum) Ginkgophyta.
This division consists of the single order Ginkgoales (Engler 1898), a single family Ginkgoaceae (Engler 1897), a single extant genus Ginkgo.
Click here for the classification scheme 
There are two extinct genera: Ginkgoites and Baiera (known from fossilized leaves).
The only living representative of the order Ginkgoales is the Ginkgo biloba.

Form   A Ginkgo tree can reach about 30 sometimes 40 metres (100 feet) height and a spread of 9 metres. The trunk can become about 4 metres (13 feet) wide in diameter (in open areas much larger; near temples 50 m with girth 10 m grow!) and is straight columnar and sparingly branched. Some trees are very wide spreading, others are narrow. Young trees have a central trunk, pyramidal in shape, with regular, lateral, ascending, asymmetrical branching and open growth. Older trees have an oval to upright spreading growth and sometimes irregular branching and tremendous sized limbs and trunk. When about 100 years old its canopy begins to widen. The male tree usually has a slim column form and is slightly longer, the female tree has a wider crown and a more spread out form.

chichi on 'Tenjinsama no ichou', girth 10 m Aomori Prefecture, N. Honshu, Japan Photo © Hiroshi Takahashi

Wood
 

click picture for enlargement  and more photos of the wood

As said before although the Ginkgo is more like a conifer than a deciduous broadleaf tree it is neither, it has a unique position. This also becomes clear when looking at the microscopic structure of the wood. It lacks vessels in the xylem but has slightly rounded tracheids giving rise to intercellular spaces (conifers have regularly close-fitting rectangular tracheids). It has beautiful crystals (called druses) consisting of calcium oxalate. These crystals occur sparingly in the wood but are abundant in the bark. These crystals are typical for the Ginkgo.

The leaves are an easy recognizable feature of the deciduous Ginkgo biloba. They are 5- 8 cm wide and are sometimes twice as broad although they vary in size and shape. The leathery leaves have a wax layer on both sides and are slightly thicker than other Northern tree leaves. They consist of a leaf stalk and a fan-shaped dichotomously veined blade: two parallel veins enter each blade from the point of attachment of the long leafstalk and divide repeatedly into two's (picture click here) , are not often cross-connected (seldom fuse). The veins are slightly raised giving a ribbed appearance. The pores are recessed and limited thereby reducing waterloss from evaporation. The form is bilobed, it has no midrib and is fan-shaped. The leafstalk is also about 8 cm (3 inches) long causing the foliage to flutter in the slightest breeze.  The leaf resembles the leafshape of a Maidenhair fern (Adiantum), hence the plant's nickname, the Maidenhair tree.

fallen leaves  enlarge: click picture

A deep vertical slit in the top center divides the leaf into two lobes mostly on the upper part of long branches. The leaf can also have more than two lobes, esp. on the lower part of the tree. There is great variation in the degree of lobing on the same tree and this also seems to vary from tree to tree.  The colour is gray-green to yellow- to darkgreen in summer, turning in yellow and in good years a beautiful golden yellow colour in fall. Certain selected cultivars yearly have this golden yellow colour in fall.  They remain on the tree until late in the season and then can all fall rapidly in a single or a few days and even in 1 or 2 hours!

There is great variation in the degree of lobing on the same tree and this also seems to vary from tree to tree.

The form of a butterfly resembles a Ginkgo leaf.   Drawings: left - Le Ginkgo by Bernard Jeannel below - Atsuko Kato

The extract of the dried leaves is popular for their use as a diet supplement and/or herbal medicine (prescribed in Europe) for the brain, legs, eyes, heart and ears. Scientific studies show that good extracts may improve bloodcirculation and memory, prevent bloodclotting, damage by free radicals and give an improved sense of well-being and can be used for many other disorders. The leaves are also used as tea for a variety of ailments.

The fungus Bartheletia paradoxa is a living fossil like Ginkgo biloba and grows on fallen Ginkgo leaves (it is not present on leaves on the tree), it does not grow on other plant species.

Read more about this on my Usage-page.

Climate zones 3 to 9 (-30/40 to +20/40 C). So from Iceland to Australia, read my Where-page.

Nearly every arboretum or botanical garden will contain specimens. The supreme specimens are to be found on temple grounds in China, Korea and Japan. In China they also grow in forests and valleys on acidic, well-drained sandy loam (pH 5-5.5) and they are cultivated below 2,000 m (see Where-page).

Jinfo Mountain
Ginkgo has survived in some areas of China where the impact of glaciation was minimal. Populations of Ginkgo biloba are found across the country, but are generally associated with human activities.
Questions about the extent of Ginkgo biloba’s native range in China have been the subject of debate among botanists for well over a hundred years.
DNA analyses (Literature-page) have demonstrated that isolated Ginkgo populations in southwestern China, especially around the southern slopes of Jinfo Mountain (Jinfo Shan) of Nanchuan County at the boundary of Chongqing Municipality and Guizhou Province (28°53'N; 107°27'E) possess a significantly higher degree of genetic diversity than populations in other parts of the country. Southwestern China was less affected by cold air from Siberia during the glaciations.
The area has a mesic, warm-temperate climate with a mean annual temperature of 16.6°C and a mean annual precipitation of 1185mm, with Ginkgo trees growing mainly between elevations of 800 and 1300 m. The largest Ginkgo tree was estimated to be 2500 years old with a mean diameter of 3.69 m at breast height.
 

Tianmu Shan Reserve click photo to enlarge and to view more photos photo © Peter Del Tredici

Ecological work in this area, as well as in adjacent parts of Guizhou Province, has identified numerous small populations, for instance in Wuchuan County and Tuole, that can be considered to be either wild or remnants of wild plants, despite their proximity to small villages practising subsistence agriculture. Both the Jinfo Mountain and Wuchuan County populations are situated to the east of Mt Dalou. This region has the greatest biodiversity in China due to the relatively stable environment and diverse topography.  The Ginkgos on West Tianmu Mountain, which were previously considered to be wild by many researchers, may, instead, have been introduced by Buddhist monks. However, more research is needed.

For places where the Ginkgo has a special growing spot see the page Where on my homepage.

The Ginkgo can have a long life span, 1,000 or older. In China the oldest Ginkgo is about 3,500 years old!

The majority of ginkgos live as a hardy ornamental tree and, being nearly cosmopolitan, specimens are planted around the globe in almost any temperate and subtropical areas. In the USA only 0.2-2% of the total number of roadside trees is a Ginkgo, in Europe this is even less (1992). The tree is farmed extensively (esp. for its medicinal use as a herb) in Europe, Japan, Korea and the USA.

In China Ginkgo trees of more than 100 years old are listed as second class protected plants of the state. Roads and buildings should give way in order to protect them well.

Some people think there's a good opportunity to plant a Ginkgo tree on special occasions like the death of a beloved one, the birth of a child, an anniversary, moving house etc.
 
 

The Ginkgo is listed in the IUCN Red List of Endangered Plants. Although it is cultivated and planted by humans, it is endangered, and at risk for loss of biodiversity because of propagation by cuttings rather than by seed, due to human preference for male trees.

Planting: It prefers full sun to partial sun and moist, deep, well-drained soils (preferably sandy loam), but is very adaptable, so it also grows in poor soils, compacted soils, various soil pHs, heat, drought, salt spray in winter and air pollution. Fertilize 1-2 times a year. Don't mulch with shredded bark round the trunk, keep it airy. It roots deeply (photos of root system). The roots of most Ginkgos are infected by vesicular-arbuscular mycorrhizae (VAM) that play an important role in the uptake of the element phosphorus.
 

Midousuji Boulevard, Osaka, Japan 900 Ginkgo trees of 1937 in a row of 4.5 km Photo © Sando Tomoki

Plant in spring or fall. Young trees tend to grow crooked and should at first be staked. Give plenty of water (more during dry/hot periods) until they are about 6 metres (20 feet).  It is slow to recover from transplanting. In favourable conditions the Ginkgo grows from about late May to the end of August over 30 cm per year for the first 30 years of its life. In some years it doesn't grow at all, in others 1 metre of growth can occur, independent of watering or nutrients. It can grow steadily in the shady understory of a forest until there is a light gap, then it can quickly grow tall and become a dominant tree. The tree needs no pruning. If you like, pruning on young trees can be done in early spring, older trees are seldom pruned.

Gender: the tree is dioecious, male and female trees are separate.  The sex chromosomes (XX females and  XY males, just like humans) are difficult to distinguish, so the tree's gender is not easily classified. The pollen and ovules grow on the short spurts, very seldom on the leaves (Ohatsuki). Occasionally both genders are found on the same tree. After a hot summer or grown in a warm sunny position the tree produces  them more reliably.  The female tree has an abundance of ovules in pairs on stalks each containing an egg cell, looking very green on the start but turning into greenish-yellow followed by orange and brown.

Ohatsuki ovule.  More photos of old tree in Japan and ohatsuki leaves.  Ohatsuki pollen remain small photo  © Hiroshi Takahashi

 They look like cherries. It takes about 20-35 years before they appear for the first time in spring. Catkin-like pollen cones (microsporangia) containing the sperms on the male tree also grow on short shoots in spring (also after about 20-35 years) and the pollination usually takes place via the wind. The female tree can carry seeds without pollination (sterile). Variations in the cycle of pollination, fertilization and seed abscission in Ginkgo are mainly due to the latitude and the local climate of the region in which the tree is growing.

When the ovules are fertilized they develop into yellowish, plumlike seeds about 2,5 cm (1 inch) long, consisting of a large "nut" (the size of an almond) with a fleshy outer layer. The actual fertilization of the seed by free swimming sperm occurs mostly on the tree (read more here).

The propagation can also be done by cuttings (the best way to ensure the gender) or by grafting a female branch onto a male plant or visa versa.

Read further about this on my Propagation-page.

The fresh nutritious seeds (also canned with fleshy outer coat removed) are sold in markets esp. in the Orient.

The "nut" has for long been used in Chinese medicine for asthma, coughs with thick phlegm, bronchitis, digestive aid and urinary incontinence etc.

Read further about this on my Usage-page.
 

Bonsai
I made a special page about the Ginkgo as a bonsai tree.
Click here to go there.

Many garden centers sell the Ginkgo biloba. Special cultivars are for sale at nurseries.
The Ginkgo can often be found in the conifer catalogue (check out my Links-page and/or try search engines). Male trees are  often propagated from cuttings. Always buy from a reputable firm. Of course I would very much like to have male and female trees in my own garden, but I only have space for one big tree....
If you have a suitable spot then please plant a female tree or grow Ginkgos from seed (can become male or female tree), because they are so rare and when only male Ginkgos are planted it cannot survive without human intervention.
The Ginkgo is listed in the IUCN Red List of Endangered Plants.

The Ginkgo tree can grow large, therefore it is not the tree for every backyard. Selections are made to make it suitable for places with less space and also to meet with desired shapes etc. Upright, dwarf, narrow and conical, pendulous and variegated cultivars exist, search for them on the internet, ask for them at garden centers and nurseries. Cultivars  are mentioned below (but no doubt there will be many more).

Ginkgo biloba:

'Anny's Dwarf': dwarf form

'Autumn Gold': better fall colour and/or modified broad spreading growth habit, compact form, male.

'Barabits Nana': small bushy form, up to 2 metres.

'Beijing Gold': shrub form, 4 m, yellow leaves also in spring and summer ( in summer somewhat striped)

'Bergen op Zoom': small straight up to 4 metres.

'Chase Manhattan': small, tiny darkgreen leaves, compact, ideal for bonsai and rockgarden, 1.5 m

'Chichi (Icho)': smaller leaves and a textured trunk, bark has breast-shaped protuberances

'Chris's Dwarf' (or 'Munchkin'?): see 'Munchkin'

'Chotek': weeping form of  'Witches Broom'; cultivar from Czech Republic; found by Mr Horak, Bystrice pod Hostinemin. Named to tribute the house of Choteks, the family of archbishop F. M. Chotek.

'Eastern Star': female, bears abundant crops of large nuts.

'Elmwood': vertical columnar form

'Epiphylla': female. Max. 4 m h., more wide. Seeds form on rather young plant.

'Elsie': upright growing, female.

'Fairmount': slender form, big leaves, dense pyramidal crown, male, 15 m.

'Fastigiata': architectural vertical accent, nearly columnar form, slightly wider at the base, big leaves, male (also available as female).

'Geisha': female, long pendulous branches and dark green foliage which turns lemon-yellow in  fall, heavy crops of large nuts.

'Globosa': Graft on stock, bulb-shaped, compact 

'Globus': Bullet-form, big leaves.

'Golden globe': Full head and spectacular yellow fall color. Trees are unusually densely branched for Ginkgos. Young trees have full crowns that mature in a broad, rounded head. Male. (from a seedling of Cleveland Tree Co. )

'Gresham': Wide spreading horizontal branch habit. (from Gresham High School Ginkgos at Gresham, Oregon)

'Hayanari': female.

'Heksenbezem Leiden' (Witches broom): quite compact, rounded, dwarf form, branching closely grouped,
up to 3 metres.

'Horizontalis': tall and wide form, many side-branches. Wide crown. 'Jade Butterfly': dense darkgreen foliage clumps, shrubby outline, vase shaped, semi dwarf, about 3 m. 'King of Dongting': slow growing, very big leaves. 'Laciniata': large deeply divided leaves 'Lakeview': compact, conical to broadly pyramidal, male. 'Liberty Splendor': broad pyramidal form with strong trunk, female. 'Long March': Upright growing, female is cultivated for heavy crops of tasty nuts.  'Magyar': uniform symmetrical branching, upright narrow pyramid form, up to 19 metres, male. 'Mariken':  more compact than 'W.B.', tall about 3 ft, w.6-10 ft, branches more or less pendulous, graft on about 5 ft stock (P. Vergeldt; from a tree in Nijmegen). 'Mayfield': Narrower form than Fastigiata, tight upright, short branches, 9-12 m. 'Munchkin' (or 'Chris's Dwarf' ?): Upright habit and numerous slender branches,  it has a tendency to be more regular in shape. Most leaves do not exceed the size of a quarter and are very dense on the plant. May eventually reach 6 ft but growth rate is around 4'' a year.  'Ohasuki': up to 4 metres, halfround big leaves, female. 'Pendula': branches more or less pendulous ("weeping"), slow growing, decorative. 'Prague or Pragense': low spreading and parasol-shaped. 'Princeton Sentry': well known cultivar, slow growing, big decorative leaves, upright conical form gives very formal focal point, male, 30 m. Improved "Fastigiata". Name derived from tree in Princeton Cemetary. 'Rainbow': striped with green/yellow leaves, about 3 m. Improved 'Variegata'. Remove green leaved branch immediately. 'Salem Lady': female from Oregon. 'Santa Cruz': female, low, spreading, umbrella-shaped. 'Saratoga': dense branches, small yellow-green leaves, slow growth, rounded outline, male, 10 m. 'Shangri-La': fast growing with compact pyramidal form, 14 metres, grows somewhat faster, male. 'Spring Grove': dwarf, very small and compact, about 3 m. 'Tit': = Chichi (Icho). 'Tremonia': small, pyramidal form, very big leaves, female, 10 m. 'Troll':   compact 'W.B.',  leaves vary from normal to rounded (Johann Wieting; from a tree in Krefeld, Germany. 'Tubifolia': slender leaves form sort of tub shape, slow growing, decorative, small tree, fairly compact branching, about 3 m. 'Umbrella': compact, densely branched, different leaf-forms and sizes. 'Variegata':shrub form with variegated foliage,  some leaves 'halved' green and gold, others striped and others half gold/half striped, up to 3 metres, female. It often reverts to green (see 'Rainbow'). Half-shaded position. 'Windover': broad oval outline, shade tree, 17 m. 'W.B.' ('Witches Broom'): dwarf form, compact, rounded, lightgreen leaf, closely grouped branches, about 2.75 m. can also be grown as a bonsai

'Autumn Gold'   Stamp People's Republic of China 1981 Ginkgo bonsai   'Witches Broom'