American wisteria is a woody vine that produces beautiful hanging clusters of purple flowers. This species is native to North America. It is a good alternative to the Japanese and Chinese wisterias that have become invasive in some areas.
Size and method of climbing:
American wisteria can grow 20 to 30 feet long. It is a twining vine. Twining vines climb by twisting their stems or leaf stalks around a support. This type of vine grows well on trellises, arbors, wires, or chain-link fences.
Native geographic location and habitat:
American wisteria is native to North America, mostly in southern states, as well as a few counties in Illinois.
The opposite leaves are pinnately compound, with 9 to 15 leaflets.
Purple, pea-type flowers in dangling clusters. The clusters are 5 to 6 inches long, shorter than those of Asian species. They have a mild fragrance. Flowers are produced in mid-summer.
Fruit are similar in appearance to pea pods. Many parts of the plant including the seeds are poisonous to eat.
Full sun is preferable, but this vine will also tolerate partial shade. A moist, well-drained, slightly acidic soil is best. Avoid compaction. Wisteria often do not produce flowers for the first five to ten years. To encourage flowering use nitrogen fertilizer sparingly and use a fertilizer that provides phosphorus, following label directions. Proper pruning will also encourage flowering. After flowering, prune excess growth back to 6 inches. These pruned stems will continue to grow. In winter, cut them again so that each stem has two to three buds left. Proper pruning not only encourages flowering, but it also helps to manage the size and shape of the vine. Wisteria vines are heavy and require sturdy supports.
List of pests and diseases:
American wisteria is not susceptible to any serious pests or diseases. It is tolerant of black walnut toxicity.
Alba American wisteria (Wisteria frutescens ‘Alba’):
This cultivar has white flowers.
Amethyst Falls American wisteria (Wisteria frutescens ‘Amethyst Falls’):
Lilac flowers are produced at a younger age, from 2 to 3 years old.
Nivea American wisteria (Wisteria frutescens ‘Nivea’):
This cultivar also has white flowers.