Lake Wilderness Arboretum is a forty-acre public garden in Maple Valley, Washington, devoted to plants native to the Pacific Northwest and open daily without charge. Established as a nonprofit in 1965, it was initially designed and laid out in 1970. Once known as the South King County Arboretum, it took its current name in April 2003 after Maple Valley completed the transfer of the park and arboretum from King County that January. A defining feature is one of the world’s largest collections of Western Azalea, with more than 200 selections, highlighted by the dedication of the Western Azalea Garden in June 2000.