Since 1984. The Arboretum at Flagstaff’s Summer Plant Sale is scheduled in July to take advantage of the monsoon rains. Horticulturists at The Arboretum are propagating herbaceous perennials, vines, shrubs, and trees that are acclimated to our area and are sure to do well in your garden. The Plant Sale will feature live local musical performers, food vendors and a beer garden. The event will showcase presentations and information booths with regional specialists.In addition to the plant sale, enjoy our selection of Arboretum-themed merchandise and gardening books, special presentations and walks, as well as children's crafts for shopping parents. Private sale for members only 9am-11am.