U.S. National Arboretum, Washington D.C.

• Scope of work under Recovery Act

Amount: $9 million

Addressing critical deferred maintenance of mechanical, electrical and plumbing systems and incidental repairs to the laboratory and administration building.

Milestones - To be updated as milestones are completed.

Construction Photos

Research at the U.S. National Arboretum

The U.S. National Arboretum's mission is to both do research to improve woody trees and shrubs and ornamental plants and to showcase plants that can enhance the landscape and educate people how to use plants to better our environment. The Arboretum's Floral and Nursery Plants Research Unit has a broad program of research that has contributed important new varieties of trees, shrubs and other plants.

Among these new varieties is the first Dutch elm resistant American elm. Dutch elm disease has wiped out about 77 million American elms since the disease's introduction to the United States in 1931. In 2005, the Jefferson variety of American elm was released jointly by ARS and the National Park Service. It was cloned in 1993 from a survivor of about 300 elms planted on the National Mall in Washington D.C. in the 1930s.

Finding trees that can survive the tough life on the streets of U.S. cities is a major project for Arboretum scientists. Nine good street tree candidates have been identified in the arboretum's cultivar collection, including varieties of red maple, crape myrtle, crab apple, flowering cherry and elm. Most of the tree varieties mature at less than 25 feet and thrive in a range of U.S. hardiness plant zones.

Sometimes the Arboretum develops a plant that is as useful in the kitchen as it is in the landscape. Such a plant is Black Pearl, a striking ornamental pepper developed by Arboretum scientists, that was selected as a 2006 All-America Selections winner. This award is presented to new flower and vegetable varieties that demonstrate “superior garden performance” in nationwide trials. With shiny black leaves and glossy fruits that ripen from black to red, Black Pearl offers a temptation few pepper enthusiasts can resist. Since it went on the market in 2005, more than 2 million seeds have been sold.

Project Photographs Before Construction