A Pretty Pest That Will Take over if Left Unchecked

The burst of blooms and the perfumed air signal that summer in panhandle Florida can be very pleasant, despite the heat. Any outside activity results in encounters with a rainbow of colors and tones emanating from trees, shrubs and weeds.

Any foray into the country will yield ever changing vistas of whites, reds, pinks, blues and every shade of green from an array of native plants and trees.

All this seasonal foliage-flurry results in seed production and ultimately the colonization of new territory for each species involved. It is usually at the expense of another species, but at least with native plants it is a balanced and fair competition.

Unfortunately, there are exotic invasive species which are contributing to the season’s color pyrotechnics. One of these pretty invaders is Japanese Wisteria (Wisteria floribunda) and it is blooming plentifully from every tree, fence or any other structure it is able to climb.

The blooms are pretty and the fragrance pleasant, but control is a nightmare. Despite its attractive features, this exotic invasive vine should be removed before it becomes a problem.

There are ten species identified as Wisteria in this genus, with Wisteria floribunda native to Japan. Other members of this genus originate in China, Korea and even the eastern United States.

In its native range Wisteria floribunda is prized for its hardiness and flowering capacity. It produces the largest flowers in its genus, and they have a pleasant scent.

The vine was imported into the U.S. during the 1830’s when Japan was still a closed society. Its tolerance of a wide range of environmental conditions and profuse lavender blooms made it an ornamental in high demand.

Growth of the Wisteria vine is usually limited only to the height of the plant or structure it is climbing on. It is not uncommon to see it grow more than 65 feet in height.

Flowering occurs through June with velvety brown seedpods produced soon after. The pods are four to six inches long with black or dark brown butterbean-shaped seeds which are toxic to mammals.

The problem with Wisteria is its growth pattern. Wisteria floribunda is a vine which will grow up virtually anything in its path and, curiously enough, grow in a clockwise configuration.

By climbing into the canopy of trees or plants, it can shade them out, impairing those plants from effectively growing. Over time, Wisteria will climb and twine around other plants, eventually shading out and girdling native plants.

As a result of this aggressive and destructive behavior, Wisteria floribunda has been labeled a category II invasive exotic by Florida Exotic Pest Plant’s Council. This designation indicates its adverse effects on Florida’s biodiversity and native plants, and the need for pest plant management.

A category II invasive exotic is a plant which has increased in abundance or frequency, but it has not yet altered Florida plant communities to the extent shown by category I species. Category I species have altered native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives.

American Wisteria (Wisteria frutescens) looks similar to its Japanese cousin and grows well, but not overly aggressively, in north Florida. This native plant is a vine with somewhat more subdued blooms, but it is used in ornamental applications with fewer control challenges.

If this beauty shows up in the home landscape, be sure to remove it before it becomes a beast of a problem to control.

About the author
Les Harrison

Les Harrison is a longtime resident of north Florida, having attended public schools in three counties. He has a Bachelor Degree from the University of Florida in Journalism and a Master’s of Science from Auburn University in Agricultural Economics. He is the author of more than 2000 newspaper and magazine stories and journal articles. During his career, he held positions in private, government and educational (university level) sectors. He holds the title of Extension Agent Emeritus. He can be reached at harrison.gl@gmail.com.

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