As far as Seattle's green spaces go, this 230-acre arboretum is arguably the most beautiful. On calm weekdays, the place feels really secluded. The seasons are always on full display: in warm winters, flowering cherries and plums bloom in its protected valleys as early as late February, while the flowering shrubs in Rhododendron Glen and Azalea Way bloom March through June. In autumn, trees and shrubs glow in hues of crimson, pumpkin, and lemon; in winter, plantings chosen specially for their stark and colorful branches dominate the landscape. March through October, visit the peaceful Japanese Garden, a compressed world of mountains, forests, rivers, lakes, and tablelands. The pond, lined with blooming water irises in spring, has turtles and brightly colored koi. An authentic Japanese teahouse is reserved for tea ceremonies and instruction on the art of serving tea (visitors who would like to enjoy a bowl of tea and sweets can purchase a $7 "Chado" tea ticket at the Garden ticket booth). The Graham Visitors Center at the park's north end has descriptions of the arboretum's flora and fauna (which include 130 endangered plants), as well as brochures, a garden gift shop, and walking-tour maps. Free tours are offered most of the year; see website for schedule.