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Collection Strengths

Native species are well represented in the Smithsonian Gardens Tree Collection with numerous examples of elms, oaks, maples, sweetgums, pines, junipers, dogwoods, redbuds, fringetrees, birches, hickories, hollies, magnolias, and baldcypress trees. In addition, several exotic species, hybrids, and cultivated selections add to the diversity and interest of the collection. Some of these include saucer and hybrid magnolias, Japanese flowering cherries, crabapples, Hinoki cypresses, Gingkos, Zelkovas, and katsuras as well as exotic species of pines, maples, dogwoods, magnolias, and others. Tree species selection is targeted to complement each of the garden designs across Smithsonian museums and support sites, while showcasing the diversity of trees suitable for the Mid-Atlantic region.

Selected trees of interest include:

  • A majestic American elm (Ulmus americana) that can be found at the corner of 9th Street and Constitution Avenue, at the north end of the Pollinator Garden adjacent to the National Museum of Natural History. This elm is estimated to be nearly 200 years old, and is 70 inches in diameter, 18+ feet in circumference, and 85 feet tall.
  • An iconic double allée of brilliant flowering saucer magnolias (Magnolia x soulangeana) flanking the south approach to the Smithsonian Castle.
  • A sprawling Chinese hackberry (Celtis sinensis) at the Donald W. Reynolds Center for American Art and Portraiture, planted 1900-1910, thought to be one of the largest and oldest in the district.
  • One of the early generation of dawn redwoods (Metasequoia glyptostroboides) imported to North America—this tree acquired from Yale University’s Marsh Garden less than 20 years after the thought-to-be-extinct species was discovered in 1941 growing in isolated populations in China.
  • Several oaks (Quercus spp.) grown from seeds collected at important landmarks in America history at the National Museum of American History. Use the search function on Plant Explorer to explore the various species.
  • A number of other uncommon, interesting, and unusual trees for gardens and landscapes in the region including longleaf pine, magnolias such as bigleaf and oyama, dove-tree, chestnut hybrids with significant American parentage, mountain silverbell, Franklin tree, sourwood, red bay, prickly-ash, hop tree, Allegheny chinquapin, indoor black olive trees, disease-resistant American elms and elm hybrids, and Darlington, live oak, Nuttall, and Chinese evergreen oaks.

Check out one of SG Arborist Jake Hendee’s Let’s Talk Gardens webinars here: