In 1920, the 430 acres which is now to the north of East Madison St. and just west of Madison Park was divided into two and the eastern 230 acres was developed into what is now the Broadmoor neighborhood and golf and country club and the western 200 acres was given to the city who developed a park and arboretum on the site.  The park was originally designed by James Dawson of the Olmsted Brothers firm who were a famous landscaping firm from Boston who at the time were brought in to design a lot of the parks in the area.  The Washington Park Arboretum displays over 20,000 trees, shrubs and vines, more than 10,000 of which are catalogued in collections and some are on the endangered species list.  You will find plants from all over the world many of which were collected in the wild including pine, spruce, cedar, fir, magnolia, Japanese Maple, rhododendron, azalea and several others.  Admission is free, the park is open from dawn to dusk and the Graham Visitors Center is open form 10am to 4pm seven days a week.
The Washington Park’s mission statement is:
“The Washington Park Arboretum is a living plant museum emphasizing trees and shrubs hardy in the maritime Pacific Northwest.  Collections are selected and arranged to display their beauty and function in urban landscapes, to demonstrate their natural ecology and diversity, and to conserve important species and cultivated varieties for the future.  The Arboretum serves the public, students at all levels, naturalists, gardeners, and nursery and landscape professionals with its collections, educational programs, interpretations, and recreational opportunities.”
Lake Washington Blvd. runs through the Arboretum and runs parallel to Arboretum creek which is within the park in its entirety.  At the south end of the park where Lk. Washington Blvd meets East Madison Street there is a ball park/playfield called the Washington Park Playfields.