Regional Gardening Reports :: National Gardening Association

In the Garden:
October, 2006
Regional Report

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Plant explorer Patrick Nutt demonstrates how to fertilize the giant Victoria Amazon water lily, 'Longwood Hybrid'.

Non-Native Ornamentals

My gardening tendency is to promote native plants for ecological reasons. American native plants have survived the test of time. Native species and native-derived cultivars are usually disease-resistant and adapt easily to light, soil, and moisture conditions. They are low-maintenance, many are drought-tolerant, and many provide food for native wildlife.

Yet at a recent event, Plant Exploration -- 50 Years, 50 Countries, 50 Expeditions, I was reminded of the beauty and diversity that introduced trees, shrubs, and tropicals bring to our gardens (public and private) and homes. As summer eye candy, New Guinea impatiens top the list. Their bright flowers, colorful foliage, and sun/shade tolerance combine to make these introduced tropicals an American hit.

The white-flowered Japanese crape myrtle (Lagerstroemia fauriei) is a powdery mildew-resistant alternative to the common crape myrtle (Lagerstroemia indica). This fungus resistance and the tree's shape, size, and exfoliating bark make it an attractive ornamental specimen and street tree in zones 6B to 10A.

At Longwood Gardens' heated water lily pools, visitors of all ages stand fascinated by the huge, coppery red-rimmed leaves and creamy white flowers of the Victoria amazonica 'Longwood Hybrid'. This exquisite specimen is not for the home water garden. Seeing it, though, is an awesome experience, here as well as at the Missouri Botanical Garden and the Royal Botanic Gardens, Kew, in England. Better yet is watching Longwood hybridizer and plant explorer Patrick Nutt simulate pollination by a scarab beetle by halving a ripe flower bud.

Plant Explorers
Many exotic ornamental plants found their way here through a collaboration of intrepid plant explorers from Longwood Gardens and the U.S. Department of Agriculture starting in 1955. Their mission involved finding, preserving, and introducing foreign agricultural and ornamental plants. In 1956 renowned plant explorer John Creech collected Japanese crape myrtle seeds from Yakushima Island in Japan, which led to today's cultivars -- the mildew-resistant 'Fantasy', 'Lipan', 'Sioux', 'Tonto', and 'Yuma'.

In 1970 plant hunters Harold Winters of Longwood and Joseph Higgins of the USDA discovered orange and red New Guinea impatiens in Papua. They brought 25 impatiens (plus rhododendrons, ferns, begonias, and gingers) back to the USDA Plant Introduction Station in Glenn Dale, MD. I'll not even try listing the many New Guineas we lust for now.

Of course, many introduced plants definitely have a downside, as anyone trying to control Japanese knotweed, goutweed, and kudzu knows. Imported invasives like Japanese honeysuckle and oriental bittersweet choke out native plants, depriving birds and other wildlife of nutritious, timely sustenance.

In closing the meeting, Peter Del Tredici of Boston's Arnold Arboretum noted several areas of concern, including saving plants in their own habitats. He proposed more professional responsibility in light of the "globalization of world ecology." Said del Tredici: "The challenge we face in the future is how to continue collecting plants in a way that does not cause further disruption to our beleaguered environment." Botanical gardens should be one of the places where new plants are tested for their potential invasiveness as well as their ornamental potential."

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