Run jointly by the city and the University of Washington: 230 acres along Lake Washington holding one of the larger plant collections in North America, strongest in maples, hollies and conifers. Azalea Way is the spring walk. The Seattle Japanese Garden at the south end is ticketed and separate — a 1960 Juki Iida design with a tea house, and the best three and a half acres in the park. Most of the arboretum is free and open.