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Author: Susan Parsons
Once you are introduced to Ginkgo biloba it becomes a favourite tree. Known as the Maidenhair or Duck’s Foot Tree, the distinctive foliage is lime green in spring and buttery yellow in autumn. The butterflied, fan-like leaves are usually divided in two at the tip and they make a honey-coloured carpet when they fall.
Every beauty has a secret and female ginkgo trees produce ‘fruit’ (actually a seed) with ovoid, foul-smelling fleshy outer layer which is peachy-pink overlaid with a silvery bloom. This is at its worst when squashed underfoot on a warm autumn day. Female ginkgos can take 20 years for first fruits to be produced.
Natural occurrence of Ginkgo biloba was originally in south east China and some wild populations possibly exist on Xitianmu Mountain in Zhejiang. This deciduous conifer, a gymnosperm, has ancient lineage to the Jurassic period and it is the only living representative of a genus known otherwise as fossils. It is now endangered in the wild.
Forests in remote mountain valleys near the border between Zhejiang and Anhwei provinces in China contain a possible natural population of Ginkgo trees. In Tuolo, a village in south-west China there are ‘wild’ ginkgos around 1,100 years old and there is said to be a natural population of old ginkgos in Wuchan County. The ginkgo is the city tree of Chengdu, Sichuan and a tree near the Tianshi cave is believed to be more than 1,200 years old (i). However Maidenhair Tree has been in cultivation for so long it is difficult to determine whether any natural stands remain.
Dr Peter Valder in “The Garden Plants of China” (1999) refers to an 800-year-old ginkgo at Jianshan, Zhenjiang and “The King of Trees”, a ginkgo said to be 1,000 years old, which grows in a courtyard at Tanzhe Si (temple), southwest of Beijing.
There are many ginkgo trees in Beijing Botanic Garden and a bonsai (penjing) specimen which is said to be more than 1,300 years old. It is noted that this age turns up quite commonly for ginkgos which would place the origins to about 700 CE or in the Tang dynasty.
An ancient tree, known as Ginkgo Queen, grows in the ‘wild’ in Chongqing and in a rural area near Guilin in Guangxi is a ginkgo forest of one million planted trees.(i)
Thomas Pakenham in “Meetings with Remarkable Trees” (1996) describes the fine ginkgo specimen at which was brought to Kew for the Dowager Princess of Wales’ new arboretum. This tree has breast-like protruberances on the trunk called ‘chi-chi’ of which it has been said they are “like teats on a cow’s udder” confirming the Japanese belief, recorded in 1712 by Engelbert Kaempfer in Japan, that ginkgo is ‘the tree of milk’.”
Ginkgo tree is the symbol of Tokyo Metropolitan Area and a tree at Tsutsuga Temple in Hiroshima is more than 1,100 years old. Ginkgos in Ibaraki province are valued as living national treasures and ginkgo is the ‘state’ tree of Osaka Prefecture.
In South Korea, nineteen ginkgo trees have been designated Natural Monuments and 813 ginkgos are protected as ancient living trees. It is believed that the ginkgo was brought to Korea from China by Buddhist monks.
The popularity of the ginkgo in the United States, where it was introduced in 1784, led to the formation of the International Golden Fossil Tree Society in Lombard, Illinois.
In Europe, important specimens of ginkgo are grown in Utrecht, The Netherlands and Geetbets in Belgium.
Dr Roger Spencer in “Horticultural Flora of South-Eastern Australia” (1995) says the finest specimen in Victoria, and possibly Australia, is at Geelong Botanic Gardens. This female tree, 18m tall with aerial roots, has been declared a Heritage Tree by the Australian National Trust.
Ginkgo was included in the Camden Park Nursery List (NSW) in 1843 but the mature tree in Geelong was grown from seed obtained from China in 1859.
In Australia, Ginkgo grows best in latitudes south of Sydney and Perth. In Adelaide there is a 100 year old tree in Kingston Terrace and a notable tree in Medole Court at the University of Adelaide. In Sydney’s Hyde Park is a ginkgo near St James Station planted c. 1900 and an old ginkgo grows at The Gorge, Launceston, in Tasmania. There is a fine specimen in Albury Botanic Gardens,
a male tree donated by Royal Botanic Gardens Melbourne aged around 70 years old. Its height in 2009 is 23 metres and width of canopy 21 metres.
The Virtual Fossil Museum website lists a ginkgo leaf fossil (Ginkgoites australis) from the Koonwarra Fish Beds at Leongatha in East Gippsland, Victoria, which measures 50 x 48mm.
In “Trees & Shrubs in Canberra” (1991) Professor Lindsay Pryor and Dr John Banks say the oldest known surviving ginkgo in Canberra is a female tree, one of a pair, planted in the Quadrangle of University house in 1953. Its first fruit crop was in 1985 and, in autumn 2009, it was tasseled with a smelly bounty. In 1987 three additional ginkgo saplings were planted near the reflecting pool in the courtyard.
In the John Banks Courtyard, at The Fenner School of Environment & Society at the ANU, formerly the Forestry Courtyard, six ginkgos were planted in the late 1960s down one side of the quadrangle. At least two are fruiting females, which produce a seasonal pungent aroma identified by the Professor of Forestry, Peter Kanowski, as ‘noticeable’.
In Weston Park the most splendid tree, about 15m tall, is a male ginkgo in the grounds of Hobday’s Cottage (Yarralumla Gallery and The Oaks Brasserie) under which you can eat lunch.
Outside the Treasury Building in Parkes are four handsome spreading ginkos, two male, two female, which dangle their fruit and foliage at eye height for passersby to admire.
The DISMUT information system to support the management of urban trees updates a census of street and park trees in Canberra, completed in the mid-1990s (iii). The DISMUT list shows that Canberrans and visitors to the Capital can visit ginkgo trees in the suburbs of Belconnen through single trees at Crace Street, Weetangera; Denny Street, Latham; Lightfoot Crescent, Florey; Ryle Place, Flynn; Jauncey Place, Charnwood and Bazley Street, Fraser. In Tuggeranong there are plantings in Section 34, Greenway (7 trees); Babinda Place, Isabella Plains; Rohan Street, Richardson (4 trees); Upton Street, Monash (5 trees); and Dennys Place, Macarthur (3 trees). There are six well-known ginkgos in Watt Street, Campbell (planted in 1958), and one tree in Baker Street, Ainslie.
Kernels of ginkgo are prized as a delicacy and medicine in China and Japan and, increasingly throughout the world. ‘Ginkgo nuts’ are usually roasted before being eaten but this is an acquired taste.
On a visit to Canberra in 2003, landscape architect Professor Richard Clough said two ginkgos were included among food plants sent by Sir Joseph Banks from Kew to Australia on the First Fleet. Clough later provided a recipe from Japan for the preparation and eating of ginkgo but roasting the ‘nuts’ or breaking the white shell and the thin brown inner skin, parching them in salt and sake and serving them and skewered on pine needles.
In 1988 staff at the Horticultural Services Unit in Weston had correspondence with a doctor at a pharmaceutical company, Chemin Fin Delez, in Switzerland about his research project to improve per acre performance in plantations of ginkgo covering 180ha in Bordeaux, France and 455ha in South Carolina, USA, a total of 17 million trees. The major product line of the company was based on an extract from dried leaves of Ginkgo biloba.
In Australia, and throughout the world, health food shops offer capsules of Ginkgo extract as an aid to memory and debate continues regarding its efficacy in the treatment of high blood pressure, poor circulation, memory loss and even Alzheimer’s disease. Dr Joachim Volkner has been awarded a German medical prize for research work on ingredients in ginkgo leaves which were found to be beneficial to circulation of blood and inhalation solutions of essence from the leaves for treatment of catarrh.
Horticulturist Frank Grossbechler has been collecting ginkgo seed in Canberra for Yarralumla Nursery where the trees are being raised for the Arboretum. His main source for seed is the female tree at University House and two or three trees from the Forestry planting at the ANU. Not all the female trees bear fruit every year.
Grossbechler waits until April when the fruit falls naturally. Sometimes he climbs thetrees and gives them a shake so the fruit falls onto tarpaulins. He brings them home covered with garbage bin plastic bags so the smell does not permeate his car. From one tree he can harvest 1,000 seeds.
The ginkgo fruit is left to ferment for a few days then he hoses it through a coarse sieve to blast off the flesh. The pretty kernels are then ready for planting and he sells about 5,000 seeds a year to the Nursery. The seed is sown and left in the open as frosts are good for easier germination.
For the Arboretum, four kilos of seed was brought Australia from China in December 2006, supplied by Beijing Forestry University Forest Science Co. After passing through quarantine in Sydney it was sown in boxes at Yarralumla Nursery in Canberra. Nursery Manager Michael Kidd says it takes 12 months for seedlings and another year until planting out and 600 young trees will be planted in autumn/winter 2009.
In August 2009 the National Bonsai and Penjing Collection of Australia received two ginkgo seedlings raised from the ‘sacred seeds’ sourced from temple gardens in China. These will become part of the ‘Arboretum in Miniature’ project, specimens of the same age and provenance as selected trees planted in the ground at the Arboretum. Many visitors will gain pleasure from seeing both the small and full-size specimens in relatively close proximity on the site. (iii).
The goal is to grow as many of the arboretum species in bonsai/penjing form as possible. It will take a number of years before these very young and unformed specimens take on the characteristics and qualities of mature miniature trees.
There has been an early and continuing interest in raising Ginkgo biloba in Australia.
Our search through the original handwritten tree records at the Government’s Yarralumla Nursery in Canberra show that Ginkgo biloba seed was received in the ACT in 1947 from New Zealand and the following year from the NSW Forestry Commission and the Australian Forestry School in the ACT.
“Male and female” ginkgos were sent from Japan in 1955, seed from New York in 1956, and from the Australian Embassy in Japan in 1962. Plants of the cultivar ‘Fastigiata’ were sent from Hazelwood Bros in Epping NSW in 1949 and again in 1963.. At this time Kershaw in St Ives, NSW was sending bundles of 200 and 400 seeds of Ginkgo biloba to Canberra and Cohen in Turramurra sent 100 plants.
There are now various cultivars available including ‘Laciniata’ with deeply dissected leaves, ‘Pendula’ with weeping branches, male clones ‘Saratoga’ and ‘Autumn Gold’; from the USA, and ‘Variegata’ with striped yellow/green leaves from France.
Yamina Rare Plants at Monbulk, Victoria, stocks Ginkgo biloba cultivars ‘Fastigiata’, ‘Autumn Gold’, ‘Queen of Fruit’ (female), ‘Pendula’, the standard form ‘Mariken’ and ‘Saratoga’.
Note: The author of this essay, Susan Parsons, has asked for additional information about the ginkgo. In particular she has asked for e-mails about any notable ginkgos that you might have seen, or plan to visit, anywhere in the world. She would like to know the place, age, description and provenance if you can obtain it. Please do not include photographs of trees but send information to: firstname.lastname@example.org
(i) “The Ginkgo Pages” visit: www.xs4all.nl/~kwanten/more.htm
(ii) Information supplied by Professor Cris Brack, formerly of the ANU and now Chair of Forestry, Waiariki Institute of Technology in Rotorua NZ, 2009.
(iii) Information from Canberra-based Dr Roger Hnatiuk of the NBPCA.