The Hardy Plant Society of Oregon, commonly known as HPSO, is a non-profit volunteer organization for all gardeners: beginning or experienced, amateur or professional. Founded in 1984 and dedicated to the promotion of hardy herbaceous perennials, the Society now has over 2,600 members throughout the Pacific Northwest in Oregon, Southwest Washington, and beyond. This year, in June 2019, HPSO will be hosting the Study Weekend. Learn more about the Study Weekend here.Open Gardens Garden Travel Plant Sales Speaker Programs |