Olmsted Green Ash

There are 16 species of Fraxinus in North America that are now on the International Union for Conservation of Nature (IUCN) Red List of threatened species, largely a result of the impacts of the emerald ash borer (EAB).

The U.S. Capitol Grounds is home to two critically endangered species — green and white ash. The grounds have 10 individuals in our collection on Capitol Square, three of which have been alive since 1894. These undergo systemic insecticide trunk injections bi-annually to preserve these specimens for future generations.

There is one original green ash tree still living on the U.S. Capitol campus today.

(Photo coming soon.)

About the Olmsted Originals

Landscape architect Frederick Law Olmsted's 1874 General Plan for the U.S. Capitol Grounds sought to create a setting to accentuate the monumentality of the Capitol Building. Approximately 45 of Olmsted's trees remain today, having endured more than a century of urban life on the front stage of American democracy.

Each tree has its own unique features and preservation challenges, and the Architect of the Capitol's arborists employ industry best management practices to ensure these trees are given the very best care to remain safely in the landscape for current and future generations to enjoy.