WASHINGTON, March 4--The U.S. National Arboretum here celebrates its 70th anniversary starting Thursday, March 7, with a six-month exhibit that features new plant releases, discoveries and inventions of U.S. Department of Agriculturescientists, said Thomas S. Elias, director of the arboretum. The media is invited to view the exhibit beginning at 10 a.m. on March 7.

“'Celebrating Science: 70 Years of Discovery’ highlights the many accomplishments of the arboretum since it was established by an act of Congress,” Elias said. The arboretum is operated by USDA’s Agricultural Research Service.

Scheduled activities include special exhibits, dedication of the entry court of the National Grove of State Trees, release of a new dwarf crape myrtle and a special exhibit of dried and live floral plants from South Africa.

“The South African exhibit will feature plants that show the area’s unique diversity and richness of flowering plants,” Elias said. “Especially interesting is the incredible assortment of exotic bulb plants related to such well-known flowers as gladiolus and amaryllis. Many of the flowers on display are virtually unknown to U.S. growers, nurseries and consumers.”

An exhibit in October and November will highlight exotic and rare cut and potted plants from South Africa. ARS has begun a cooperative research project with South African small farmers to develop and introduce U.S. consumers to these plants.

Scientists at the arboretum have developed more than 650 new trees, shrubs and floral plants. In addition to creating azaleas of many different colors and magnolias with long-lasting blooms, they search the world for superior floral and woody landscape trees and shrubs.

Through classical breeding and genetic engineering, the scientists improve the plants in some way, such as increased cold tolerance, greater resistance to disease or insects, or more tolerance for urban pollution.

Accomplishments of the arboretum over the years include:

* Development of Bradford, Whitehouse and Capitol ornamental pear trees. The Bradford pear is among the top 10 most widely planted ornamental trees in the eastern United States.

* Nineteen dwarf viburnums such as Shoshoni and Eskimo. Dwarf viburnums are ideal for foundation planting, rock gardens, borders and low hedges.

* More than two dozen new crape myrtle cultivars. These varieties are typically less than 16 feet tall, resist mildew and flower in a range of colors from light lavender to coral pink. Their mottled bark changes color throughout the year, from near-white to light brown and sandalwood to gray-brown, chestnut and mahogany.

*“Little Belle Blue,” a Eustoma (lisianthus).Developed as the first true genetic dwarf selected from tissue culture, this native plant will bloom for up to 2 months. The new cultivar was created by combining classical breeding and biotechnology to make these flowering, wild plants dwarf and bushy. Grown as either a potted or bedding plant, this new crop can be sold as a seed-produced annual bloomer.

*The USDA Plant Hardiness Zone Map. Commercial growers use the map to help decide when to ship living plants throughout the United States so they will survive if planted when received.

“Research at the National Arboretum goes far beyond developing new and better varieties,” said Elias. “Arboretum scientists develop and implement new technologies for the U.S. floral and nursery industry to keep them competitive in world markets.”

These technologies include the use of genetic engineering to improve floral and woody plants; new greenhouse and field production methods to produce mature plants in less time; improved plant and tissue culture techniques for faster selection and identification of desirable plant characteristics, and better methods for detecting and identifying plant pathogenic viruses and bacteria and controlling them.

Each year, nearly 500,000 visitors tour the National Arboretum’s grounds and exhibits set on 444 acres in northeast Washington, D.C. The arboretum is open from 8 a.m. to 5 p.m. daily, except Christmas Day. The address is 3501 New York Avenue, NE.

Scientific contact: Thomas S. Elias, U.S. National Arboretum, Agricultural Research Service, USDA, Washington DC 20002, phone (202) 245-4539, e-mail [email protected]