Types of Purple Outdoor Flowers

Annuals

• The Swan River daisy is an Australian import that comes in many colors, with purple and violet among them. Use the cultivars of this 18-inch-high annual, since they bloom longer than the parent species does, according to the Missouri Botanical Garden. The wishbone flower has the reputation of doing best in shade. It grows to 12 inches tall and blooms from June until a killing frost occurs, generating dark purple, trumpet-shaped flowers with lighter violet highlights. Annuals such as morning glory, toadflax and sweet pea come in cultivars that have purple flowers.

Broadleaf Evergreens

• Several kinds of evergreen azalea are suitable if you desire purple flowers outside your window, since most work well as foundation plants. Among the cultivars with purple flowers is Corsage, a 3- to 4-foot-high type that blooms during April and May. Herbert and Girard's Fuchsia are cold hardy to U.S. Department of Agriculture plant hardiness zones 4, while Conlep requires warmer weather to survive, growing from zones 7 through 9. Oleander, wall germander and the glory bush are other broadleaf evergreen options with purple flowers.

Perennials

• Cast-iron plant, purple milkweed and bugleweed are a few of the perennials for purple flowers you can plant outdoors. The aster family has multiple members with purple blooming ability. Included on this list are the New England aster aromatic aster and the spreading aster. Hosta, ironweed, toad lily, Pasque flower, wild sweet William, bee balm, lobelia and blazing star all have purple flowers. USDA zones 3 through 8 are appropriate settings for the purple coneflowers and its many cultivars, including Little Giant, Ovation and Vintage Wine.

Deciduous Shrubs

• Fascination, Empire Blue and Harlequin are purple-flowered forms of the butterfly bush, a Chinese shrub grown in butterfly gardens. Attraction, Purple Plum, Nanho Purple and Purple Emperor are other candidates if you love purple flowers. In zones 5 and 6, the coldest zones these deciduous shrubs survive the winter in, trim the plant to the ground in winter; it comes back strong in springtime. Different cultivars of mint shrub, crape myrtle, bush clover, bigleaf hydrangea and a handful of hybrid magnolias possess purple flowers.