Lee Valley & Veritas Gardening
Lee Valley 35 Years  
  Volume 8, Issue 8 - August 2013    
Ginkgo: The Maidenhair Tree
  Princeton Sentry ginkgo
  Ginkgo biloba 'Princeton Sentry' in late fall.
Early in my gardening career, I went to a nursery with the simple task of finding a filler plant for a sunny backyard corner. After seeing at least a dozen perfect candidates, I decided to buy an unimpressive looking tree offered at an impressively low price. I could tell that its slim, upright form would fit my backyard space perfectly and its bright-yellow foliage would add cheer to the garden. That fall evening, I carefully planted and staked it, and watered generously. The following morning, the branches were shockingly bare and a small heap of amber-colored leaves lay on the ground. As a novice gardener, I believed my care had killed the tree. Overwhelmed by guilt, I was determined to find out what had gone wrong with my Ginkgo biloba 'Princeton Sentry'.

First of all, I was relieved to learn that I was not a tree killer. The ginkgo simply has a deciduous habit and sheds its leaves in the fall, usually all at once, which many gardeners find convenient. Botanically, ginkgo is an odd coniferous tree with a lifecycle similar to that of a pine. There is a significant difference though: a ginkgo is dioecious, meaning the male and female structures are produced on separate trees. In North America, male cultivars are more easily found in nurseries, likely because the female trees produce an abundance of apricot-like fruit that creates a pulpy mess and emits a foul odor when it falls and splits. In Asia, where ginkgo fruit is considered a culinary delicacy and is used in herbal remedies, female trees are more prevalent. Although the raw pistachio-like seed kernels taste somewhat like bitter almonds, they lose their bitterness when cooked.
Ginkgo leaves
The ginkgo tree's leaves resemble the fan-shaped leaflets of the maidenhair fern, shown above.
The name ginkgo is derived from the Japanese language (although many publications claim it's from Chinese) and means silver apricot. Biloba roughly translates to "two lobed", referring to the fan-shaped, notched leaves that resemble maidenhair fern (Adiatum spp.) leaflets; hence, its other common name, the Maidenhair tree. Ginkgo trees flourished long before the evolution of a network system of veins in plant leaves, so instead of prominent veins and a midrib, ginkgo leaves are fan-shaped with hair-like veins radiating outwards. They grow spirally on short spurs and have a bluish-green color that is eye-catching in summer but truly breathtaking in fall when it turns to a stunning gold. The tree's ash-grey, fissured bark is also attractive, particularly on young specimens.

Ginkgo's prehistoric past dates to the geological period called the Permian (about 299 to 251 million years ago). The ginkgo as we know it today evolved significantly later during the lower Jurassic period (about 200 to 176 million years ago). Ginkgo is classified as a living fossil and was believed to have been long extinct until its rediscovery by German botanist Engelbert Kaempfer in 1691. Like other living fossils, the ginkgo is completely unlike any other living plant, although it does share a few features with the cycad, an even older specimen. It differs from its closest relative in that it has deciduous leaves instead of needle-like evergreen foliage, and its seeds are enclosed by a fleshy, fruit-like structure instead of cones.

Paradoxically, the ancient ginkgo can grow in a modern city environment where many other trees can't survive. This is due to its excellent adaptability; tolerance to pollution, salt and heat; and high resistance to many diseases and pests. The tree, which requires a full-sun location, is hardy to Canadian zone 5A and will easily survive mild winters. It has gained popularity as a city specimen in temperate regions throughout the world.
Spring Grove ginkgo in summer   Spring Grove ginkgo in autumn
The very bushy and compact semi-dwarf 'Spring Grove' in summer.   The same specimen with the beginnings of its autumnal leaf color.
  Ginkgo brilliant yellow fall color
  The tree's fall color could rival even that of brilliant yellow birches.
When considering a young maidenhair tree, remember it has the potential to grow into magnificent maturity with massive, horizontal branches and a trunk more than 30m (98') tall. It has an open, airy framework that casts only a light shade despite its impressive size. The ginkgo planted today under ideal conditions can grow to see great-grandchildren of your great-grandchildren, as the maidenhair tree is known for its impressive longevity.

Unless you have a large garden, when buying a ginkgo it's wise to choose a narrow, pyramidal cultivar such as 'Lakeview', 'Magyar', 'Shangri-la' or my 'Princeton Sentry', which still hasn't overgrown its backyard corner. If space is an issue, dwarf cultivars are the perfect solution. Some specialized nurseries offer miniature ginkgos such as the tiny 'Munchkin', the dense 'Troll', and the globe-shaped 'Mariken', 'Gnome' and 'Chase Manhattan'. Dwarf maidenhair trees are well suited for containers and balconies and make excellent bonsai candidates. For enthusiasts of unusual forms, consider the weeping 'Ross Moore' and pendulous 'Weeping Wonder' for small gardens, and the 'Pendula', which has a horizontally arching character, for larger gardens. Variegated cultivars are available in semi-dwarf sizes only, about 4m (13') at maturity. Though hard to find, my favorite is 'Variegata', which features white-striped foliage with the occasional all-white leaf. New cultivars with yellow variegated foliage include 'Beijing Gold' and 'California Sunset'. Like most variegated plants, they should be sited in dappled shade to prevent the two-tone leaves from scorching in summer sun.
My maidenhair tree 'Princeton Sentry' gracefully does its job of filling the backyard corner. It now has company in the form of a bushy, semi-dwarf ginkgo called 'Spring Grove'. These two will be joined by a potted miniature ginkgo one day, probably soon. Their handsome silhouettes, unusual foliage with excellent fall color, and amazing prehistoric past provide a fascinating conversation piece in any garden.

Text and photos by Gina Dobrodzicka

Gina Dobrodzicka is a freelance writer and trained horticulturalist who volunteered with Master Gardeners of Ottawa-Carleton for five years. Currently, she volunteers with the Vancouver Master Gardeners Chapter, the South Surrey Garden Club and Darts Hill Garden Society. She recently re-established her landscaping company. Her website is www.gdgardendesign.com.
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