Each year, I look forward to watching the bleak winter landscape begin to come to life as if transitioning from black and white to Technicolor. Yellow is one of the first colors to appear with the flowers of forsythia and our state flower, yellow jessamine. As I was driving to work this week, I noticed a new color emerge amidst the roadside trees.
The spectacular display of lavender is the result of Chinese and Japanese wisteria (Wisteria sinensis and Wisteria floribunda). The pendulous racemes (clusters) of flowers are breathtakingly gorgeous, but their aggressive growth habit overshadows their beauty. These non-native, invasive vines will shade and girdle other plants, even sizable trees. When girdled trees die, the increased sunlight reaching the forest floor allows new wisteria seedlings to grow and flourish.
While still commercially available, do not be tempted to plant Chinese or Japanese wisteria. Though you may keep these aggressive growers under control, there is no guarantee the future property owner will keep the plant from becoming a menace. Instead, choose the native American wisteria (Wisteria frutescens) that offers comparable beauty without the sinister growth habit. It’s true the flowers of American wisteria are a bit less showy, but I think you’ll find they offer just as dramatic an effect without posing an ecological threat. Named for its dark lavender-hued flowers, the selection ‘Amethyst Falls’ is a vigorous climber that is attractive to butterflies and other pollinators and is deer and drought resistant. How great is that?
A plant tag with the plant’s scientific name will help you choose the native American wisteria over its Asian relatives, but some characteristics can help you distinguish them in the landscape. Chinese and Japanese wisteria generally flower earlier and have more elongated flower clusters than American wisteria. Also, the seed pods of Japanese and Chinese wisteria are hairy compared to the smooth seed pods of American wisteria.
When it comes to plant sharing, I’d recommend you kindly pass if a friend wishes to gift you a piece of his or her wisteria unless you are absolutely certain it’s American wisteria. In the case of non-native invasive species, you’re better safe than sorry. For more ideas on vines that can be used in the home landscape, visit HGIC 1101, Vine Selections for Landscaping.