Wisteria frutescens
American Wisteria
Mature Size, Growth, Longevity
A climbing vine, 15-30' high (occasionally to 40') and 4-8' wide. Not as aggressive and spreading as the Chinese Wisteria and the other Asiatic types. A vigorous grower, with a fast rate of growth. Long-lived, 50-100 years.
Native Range
Kentucky Native — Native to parts of the eastern United States, from Virginia to Illinois, south Florida & Texas, including several Kentucky counties. Often found in moist to wet thickets, swampy woods, & at the edge of streams & ponds. Introduced into cultivation in 1724.
Flower and Fruit Details
June-August, fragrant, 3/4", monoecious, pea-like flowers in showy 4-6" drooping racemes, pale lilac-purple w/ a yellow spot, often after leaves emerge. Initial flowering sometimes takes 2-5 years. Regular pruning will help encourage flower production. The fruit is a smooth, narrow, compressed, flattened, 2-5" long, brown legume seed pod, ripening in the summer, poisonous to humans, and with very low wildlife value. The pods split open in the fall. Seeds are rounded.
Leaf and Bark Features
Deciduous: The 7-12" long, alternate, compound, odd-pinnate leaves each have 9-15 lance-shaped, elliptic-ovate to oblong-lanceolate, glabrous, deep green, 1.5-2.5" leaflets, which are slightly pubescent beneath. Bark is brownish-gray to reddish-brown in color.
Culture and Care
Full sun=best flowering; tolerates shade. Prefers acid, organic, fertile, moist, well-drained soil; tolerates clay. Needs pH 6.1-7.5. Avoid transplanting. Tolerant of compaction/poor drainage/flooding. Tolerates heat/drought/salt/Zone 5-9. Prune to control size/shape & to promote flowering. High phosphorus fertilizer in early spring will also help w/ this, as will root pruning. No serious insect or disease problems. Occasional foliage-chewing insects & fungal diseases, but not significant.
Strengths, Weaknesses, Other Facts
Tolerates deer. 3-season interest: Spring, summer & fall. Lack of flowering may occur due to death of flower buds overwinter due to extreme cold, or too much shade, plants too young, improper pruning or too much nitrogen fertilizer and maybe not enough phosphorus. Genus name honors Caspar Wistar (1761-1818), professor of plant anatomy at the University of Pennsylvania. This vine twines counter-clockwise. Very similar to Kentucky Wisteria. "Frutescens" means shrubby or woody.
Suggested Uses
A good choice for free-standing trellises, pergolas, fences, terrace walls, and arbors.
Taxa and Plants of this Species at BCA
The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.
Wisteria frutescens 'Amethyst Falls' // Amethyst Falls American Wisteria
Shrub. Flowers bloom April to June, and are very showy, lavender-blue/purple, and very fragrant. Blooms at an early age. Introduced by Head-Lee Nursery in Seneca, South Carolina. Received the 2006 Georgia Gold Medal for its garden merit. Grows at 1/3 the rate of Asian Wisteria. Good in containers for porch or patio, or train up an arbor or trellis, or prune and stake into a free-standing tree form. Needs part to full sun. Twining stems get 10-30' tall if they have a structure to climb up. Requires support. May be trained as an espaliered vine, or used as a specimen or for screening. Good in native plant garden, cottage garden or rustic garden. More compact than some wisterias. Attracts butterflies. Trim lightly after flowering for rebloom.
BS009039