The United States National Arboretum in Washington, DC was established in 1927 by an Act of Congress, and is administered by the U.S. Department of Agricultureís Agricultural Research Service. The 446 acre arboretum is in Northeast Washington DC. Major gardens include aquatic plants, Asian collections, native collections, flowering tree collections, dwarf conifers collections, the National Bonsai & Penjing Museum, the National Capitol Columns, the National Grove of State Trees, the National Herb Garden, and of course, the Meta Garden. Additionally, the garden has very comprehensive and large herbariums and libraries. This is a large, important arboretum that is contributes a great deal to horticultural research in the United States.

The U.S. National Arboretum is in Washington DC, which is an unusual environmental area because it is the merging point of three different ecosystems: the Eastern broadleaf oceanic forest, the Outer coastal plain region, and the Southern mixed forest. This indicates that it is a particularly temperate area. It is on the border between Hardiness Zones 6 and 7. Winds and precipitation are average, and the dominant soil types are Inceptisols and Ultisols.



The National Arboretum features a solid, if not spectacular group of Metasequoias. They are not as impressive as those at the Brookside Gardens and McCrillis Gardens in nearby Maryland, possibly because of the more urban environment that this garden is in. The Arboretum received seedlings from the Arnold Arboretum and planted six of them in 1954. Currently these trees are spread out through the garden, in the Meta Triangle, the Boxwood Collection, the Asian valley, and the Azalea Valley. They are average in size, typically around 70 feet tall with bases 25 inches in diameter. Two particularly impressive trees are around 85 feet tall with bases 38 inches in diameter.

The garden researched, developed, and eventually propagated the ìNationalî tree. The ìNationalî Metasequoia is typically a particularly tall, pyramidal, symmetrical tree, with a smaller base. It is directly derived and selected from the NA#10920 seed batch from the National Arboretum, and officially introduced into nursery trade on April 15th, 1963. This was created from a seed that eventually became the Metasequoia that is at the Gotelli Pond section of the Arboretum. This tree was planted in 1966 and is currently 67 feet tall with a base 26 inches in diameter. This is a fairly average size, but it is the mother of all ìNationalî type trees. In fact through my research I verified this through taking note of all the seed sources of trees. It is historically documented that most trees received by Arboretums in 1963 were received from the National Arboretum. These trees are in fact ìNationalî type trees derived from this seed batch.

This is significant because it shows the efforts of the United States National Arboretum in producing new types of Metasequoias. It was a feat unmatched until the Dawes Arboretum, along with John Kuser of the Cook College of Rutgers University collaborated. They helped solve the ìInbreeding Depressionî problems of Metasequoias. Besides being the Official Arboretum of the United States, this Arboretum has contributed greatly to the growth of Metasequoias.

United States National Arboretum

3501 New York Avenue, NE

Washington, D.C. 20002

http://www.usna.usda.gov/

Data courtesy the United States National Arboretum

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