University of Vermont Extension 
Department of Plant and Soil Science

Anytime News Article
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GINKGO TREES
 
Dr. Leonard Perry, Extension Professor
University of Vermont
 
           
Besides being a beautiful ornamental, ginkgo (pronounced GINK-o) trees are interesting and useful for many reasons. They’re one of our most ancient plants, having been around for over 200 millions years.  They have medicinal uses, and the fruits are eaten in Asian cultures and cuisine.  In landscapes they have a lovely habit, interesting leaves, and lovely yellow fall color.
           
Another name for the ginkgo (Gingo biloba) is “maidenhair tree”, since its leaves resemble in shape those of the maidenhair fern.  Roughly triangular or fan-shaped, leaves are about 2 to 3-inches long and wide, and often have an indentation making them “bi-lobed” (hence the species name). 
           
Leaf veins are unique to this plant too, being parallel running down the leaf and continuously dividing into twos (“dichotomous”).  Ginkgo leaves are so unique that many know them, and children often collect them.  Generally they turn a lovely yellow in autumn but, if a hard frost, can mostly fall to the ground overnight. 
           
Botanically ginkgos have yet more interest, holding a rather unique position in seed- producing plants besides being the oldest in this group.  They are a “gymnosperm”, meaning the seeds don’t have a fruit around them, but are “naked seeds” (the meaning of the word in Greek).  So they are similar in this way to conifers, or cone-bearing trees, but they aren’t in this group as they were originally thought.  Yet they are more like conifers than “deciduous” trees, even though they lose their leaves in fall like the latter. 

Research shows that the ginkgo is actually more closely linked to another primitive gymnosperm, the palm-like cycads.  Similar to cycads, they’re the only plants whose sperm cells that fertilize the eggs are motile, swimming in water. Ginkgo is the only genus in the Ginkgo family, and the only link between lower and higher plants.  There are only two other plants at all closely related, but these are now extinct (as found in fossil records). Ginkgo often are referred to as “living fossils.”
           
Most gymnosperms have sexes on the same plant, but gingko is “dioecious” with separate male and female plants.  This is important to know, as the ripe seeds of the female plant are the ultimate landscape nuisance, smelling like rancid butter at best (due to butanoic acid).  For this reason, generally only male plants and male cultivars (cultivated varieties) are now found outside Asia, where fruit are often grown to eat.  The seeds have a fleshy covering, are plum-shaped, and an inch or more long.
            
Young trees are pyramidal, becoming more oval and wide-spreading.  Female trees are even more spreading and wide. Eventually trees will reach 50 to 80 feet high, and from 30 to 80 feet wide. While generally slow to medium in growth rate, younger plants under good culture can grow 10 feet in 10 years, or more.  Trees are long-lived, perhaps to 1000 years or more.  The oldest ginkgo in China, where they’re native, is estimated over 2,500 years old. 
           
The ginkgo is quite adaptable to most of the world, growing from the cold to the subtropics (zones 3 to 9), from Iceland to Australia.  It tolerates soil extremes, except for very wet, including variable soil acidity (pH), and salty soils.  Best is a deep, moist soil. Virtually free of pests and diseases, it also tolerates air pollution, and research shows it is a good choice for rising carbon dioxide levels in the atmosphere.  It resists fire well, and even survived the radiation of the atomic blast in Hiroshima!
           
Even if you don’t know plants you may know this one from the supplements sold in drug stores and seen in teas for various benefits, including its supposed help for memory and the brain.  It is used in herbal medicine, particularly in Asia and Europe, for the brain as well as legs, eyes, ears, and heart; for many disorders including blood clotting. 
           
You also may see the ginkgo leaves and leaf pattern in jewelry and art, due to its unique and lovely shape.  The ginkgo is sacred in China and Japan, often seen on official logos and religious works, and seen planted around temples. 
           
Although the straight species is a lovely tree, there are a few cultivars of ginkgo you may find with even more yellow fall color or more upright habit.  Of the latter is ‘Fastigiata’, or the male selection of it ‘Princeton Sentry.’  This reaches about 40 feet high and about 15 feet wide, making it good along streets (as long as not under power lines). Upright to 50 feet high, but slightly broader (30 feet) than ‘Princeton Sentry’ is ‘Magyar’.  Even broader  and very symmetrical in habit is the cultivar ‘Halka’.  For good fall color, consider and look for the male cultivars ‘Autumn Gold’ or Presidential Gold™  (‘The President’).  


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