The Iowa Arboretum is a nonprofit arboretum located in Madrid, Iowa that encompasses 415 acres (168 ha). It is open daily from sunrise to sunset.
The arboretum was organized in 1966 by the Iowa State Horticultural Society on the society's 100th anniversary. Its mission is to grow, display, identify and study plants for education, research, conservation, aesthetics, and for personal enjoyment and recreation.
The arboretum contains hundreds of species of trees, shrubs, and flowers arranged in 19 collections spanning 40 acres (16 ha) as follows: Butterfly Garden, Children's Garden, Columnar Trees, Conifers, Dwarf Garden, Flowering Trees, Founders Grove, Herbs, Hostas, Large Deciduous Trees, Medium Deciduous Trees, Nut Trees, Perennials, Shade Garden, Shrubs, Trees under Utility Wires, Wetland Trees, Windbreak, and Winter Interest. In addition, the arboretum contains more than 300 acres (120 ha) of native timber with woodland trails, ravines, and streams. It accepts donations.