Question: When and how do I prune the wisteria in my yard to keep it controlled?
Answer: Wisteria started blooming across our area in the past couple of weeks and you cannot help but notice its beautiful purple and white clusters of flowers along many of our roadways and in yards as they wind around fences, trees and every structure in their path. Like many people, I love the look of it when it is in full bloom. However, it must be heavily controlled to keep it from taking over your landscape and even popping through your deck boards. While it is attractive, wisteria is highly aggressive and can displace native species.
Wisteria is an ornamental vine with fruit characteristic of the Legume Family (Fabaceae). There are native, W. frutescens, and non-native types of wisteria, including Japanese wisteria (W. floribunda) and Chinese wisteria (W. sinensisand) which were introduced to the United States from Japan and China in the 1800’s for use as ornamental plants. Japanese and Chinese wisteria are considered invasive plants in New Jersey and are discouraged. Growth of the wisteria vine is limited only by the height of the plant that it climbs, often growing more than 65 feet in length. Japanese wisteria will twine clockwise around its host while Chinese wisteria will twine counter-clockwise, reaching a diameter of up to 15 inches. These vines can survive for more than 50 years. Wisteria easily reproduces by rooting at each node, via stolon, and will produce new shoots if cut back or trimmed.
With hard work and commitment, native and non-native wisteria that you wish to keep in your landscape can be controlled culturally. These vines typically attract to open or disturbed areas. Keeping a healthy ecosystem with good species diversity will help deter the vines from spreading and is great first line of defense. With judicious pruning, wisteria can be trained along a fence, an arbor, a pergola or as a shrub much like the training used in growing grape vines. This vine should never be allowed to grow in random fashion as this will allow it to quickly take over areas where it is unwanted and will be very difficult to remove. Consistent pruning throughout the growing season will control the vigorous growth and will actually encourage more blooms in the spring. Be careful not to deposit seeds and cuttings in natural areas as they can easily take root.
If you are trying to completely remove wisteria organically, it must be done mechanically. For small wisteria infestations, climbing or trailing vines should be cut as close to the root as possible. This is a labor intensive process, but will prevent wisteria from becoming a larger problem or growing into areas where it cannot be easily removed or even chemically controlled. Wisteria will continue to sprout after it has been cut, so it should be cut back early in the season. Sprouts should continue to be cut every few weeks until the fall. This will help stop growth of existing vines and help prevent seed production. Wisteria vines should be removed from bases of trees and shrubs to prevent girdling and killing them. Sizable trees have been killed by vining wisteria.
With a small infestation you can also remove the entire plant. Any type of digging tool can be used, making sure to remove roots and runners. It is important to know that any root pieces remaining in the soil may re-sprout to produce new plants.
Do you have more questions about controlling or removing wisteria? Atlantic County Master Gardeners are available Monday through Friday from 9:00 a.m. to 1:00 p.m., but samples may be dropped off anytime between 8:30 a.m. and 4:30 p.m. Atlantic County residents can contact the Master Gardener Helpline at 609-625-0056. Cape May County Residents can call 609-465-5115, ext. 3607.
Do you have a gardening related question you would like answered here? Please forward your questions to Belinda Chester, Master Gardener Program Coordinator, Rutgers Cooperative Extension Office, 6260 Old Harding Highway, Mays Landing, NJ 08330. You can also submit questions at Rutgers-atlantic.org/garden or email them to firstname.lastname@example.org; please include “garden question” in the subject line.
Upcoming Master Gardener Events:
Atlantic County Master Gardeners will be available to answer gardening questions and take samples for plant identification or diagnoses throughout the county this spring and summer. You can find us next at the Linwood Farmers Market on May 11. Our Annual Atlantic County Master Gardener Plant Sale and Community Education Event is being held on May 18th at the David C Wood 4H Center, 3210 NJ-50, Mays Landing, NJ 08330 from 9:00 a.m. to 3:00 p.m. We will have a wide range of annuals, perennials, vegetable plants, and native pollinator plants. We have speakers throughout the day on various gardening topics. Master Gardeners will be on hand to answer your gardening questions as well as ACUA Master Composters, Rutgers Environmental Stewards, and 4H groups joining us with demonstrations and information about their programs.