Dave's Garden PlantFiles - Profile page with horticultural basics, and member-contributed photos and comments. (zone 4-7) (3 photos)
Denver Botanic Gardens - Description, native range, and cultural requirements. (additional pages for other varieties) (zone 4) (2 photos). Also a page for 'Red Select'.
Heritage Perennials - Profile with description and horticultural details. (zone 5-9) (1 photo)
Missouri Botanical Garden - Plantfinder page for one of the plants growing at the garden, with usually one or more photos, horticultural information, and noteworthy characteristics. (zone 5-7) (2 photos)
(3 photos)