Wisteria

#TeachingTuesday: Wisteria

There are several species of Wisteria, but three are most commonly encountered in the landscape: Chinese, Japanese, and American wisteria (Wisteria sinensis, W. floribunda, and W. frutescens). Both Chinese and Japanese are very aggressive vines, and will escape into wild areas, strangling any other plant they encounter. American wisteria is a native vine and is not invasive. Only American wisteria should be planted in a landscape, and the other types should be removed.

American wisteria is a deciduous vine that climbs by twining around a support structure such as a fence or arbor. It is deer resistant and attracts pollinators that feed on the nectar, and it’s also a host plant for caterpillars that feed on the leaves before turning into butterflies (specifically the zarucco duskywing and long-tailed skipper butterflies). It prefers moist to wet soil, and full sun to partial shade. The showy flowers appear in late spring, and in late summer, 2-4” bean-like seedpods appear. American wisteria is a great choice for growing on an arbor, training up the side of your house using wires (it will not stick to the surface like English ivy), or covering a fence.

The best time to prune American wisteria is right after flowering, and then continue to remove long whip shoots throughout the summer every 2-3 weeks or as needed.

ID Tips

• The leaves are dark green and glossy.
• The leaves are pinnately compound, which means each leaf is made up of 5-19 smaller “leaflets” which are arranged in opposite pairs along the stem (which is called a rachis), with one more leaflet at the tip.
• The flowers are lavender-blue and bloom in clusters. They are shaped like sweet pea flowers.
• The flowers produce bean- or pea-like pods that turn tan in the late summer or fall.
• The vines twine in a counter-clockwise direction (Chinese wisteria also twines counter-clockwise, but Japanese wisteria twines clockwise).