With its beautiful lavender-colored blooms, wisteria is a popular choice for gardens, pergolas and property facades. However, knowing when to prune wisteria in winter will have a bearing on where this pretty plant grows and how it flowers in spring and summer.
Although beautiful, this vigorous vine needs to be kept under control. Trimming it at the right time and in the right way is essential. If you're unsure how to prune plants, our gardening experts can guide you through when and how to trim back wisteria.
Following the advice ahead will not only ensure that this climber flourishes, it will prevent your wisteria smothering other species, so that they can flourish too.
When to Prune Wisteria
As one of the best fast-climbing plants for privacy, Wisteria grows rapidly. So it benefits from a biannual trim, both in the summer and in winter, when the plant is dormant. This trains the vine and encourages new blooms.
New York-based landscape designer, Kat Aul Cervoni, founder, Staghorn Livin explains why for most gardeners in the northern hemisphere, pruning wisteria should be done twice a year and when. "Prune your wisteria once in the summer (July/August) after the spring flush of flowers is finished and a second time in winter (January/February) ahead of springtime growth but while the plant is dormant," says Kat.
Kat continues: "In warmer climates, pruning in summer may need to be done more than once to control growth. The two-season pruning model can be followed for all three species (Chinese, Japanese and North American), but more aggressive pruning will likely be needed for the two Asiatic species due to their much more vigorous growth tendencies. Pruning in winter helps with the shape and structure. lt also allows for the removal of any dead or wayward growth which will help the plant direct energy towards flowering in spring."
"Biologically there are some benefits to pruning wisteria in winter, but importantly there are no leaves left to obstruct your view of the branch structure," explains professional gardener, David Angelov, founder, Plant Parenthood Design, Massachusetts.
"It's a vigorous plant, so pruning wisteria in late summer allows you breathing room and less pruning in winter. The winter pruning is for the shaping cuts that you do to set up buds for next year. It’s easier to do this once another pruning has been done already."
How to Prune Wisteria
Whether you have your wisteria as a climbing plant for the front of your house, or draped over a pergola, once the leaves have dropped you will get a better view of the structure. So stand back and inspect the plant before you begin to prune it.
"If you have a view of the whole mature stem, plan out in your head which mature pieces you're going to leave," says David. "Those will be the main trunk – the architecture of the Wisteria — and they dictate where it will grow and what it will wrap around.
"I then like to get up close, and start at the farthest end, the tips. Starting from the ends, I cut back to the main stem, leaving two leaf nodes, above the node, which will reveal the structure that you want. It will allow for a cleaner look, it's a tried and true system," David continues. "Whether you have flowers next year or not, the plant will be neat and more ready for flowers the following year. If you stay in that cycle, the wisteria becomes manageable."
Kat tells us: "Once you have inspected the plant, you can also remove any dead, diseased, or damaged wood. Be sure to eliminate crossing branches to improve airflow. This is also the time to remove unwanted growth, like long, wispy shoots or overcrowded spots or any suckers at the base of the plant.
"Cutting back shoots to 2-3 buds from the base will encourage better flowering and those buds will form flowering spurs. For timing, choose a milder, dry day to avoid frost damage and be sure to use clean sharp tools for precise cuts."
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FAQs
Is Wisteria an invasive plant?
Wisteria grows rapidly, so it has a reputation for being invasive, particularly imported varieties that can quickly smother other plants, and it is a climbing plant that many avoid, and it's banned in some states.
"Both the Chinese (sinensis) and Japanese (floribunda) wisterias are considered invasive in the US, particularly in the Southeast where a warmer climate allows them to quickly grow out of control and smother other native species," says Kat. "The asiatic varieties are the most aggressive growers, so must be managed to prevent unwanted spread. There are two species native to North America, wisteria fructescens and wisteria macrostachya, that have a similar aesthetic, but grow at less explosive rates and so are much easier to manage."
"Any wisteria can potentially become invasive, even native species," says professional gardener, David Angelov, founder, Plant Parenthood. "How you manage it (or not) can make it invasive. It might have gorgeous flowers but if your Wisteria is wrapping around a satellite dish, it’s becoming invasive. So when planning to plant it, know what it could wrap around.
David says you should avoid planting wisteria next to cables, "or next to anything else that is alive. It can choke out a tree trunk; it can smother and not allow light to penetrate down, even if it’s a native species."
He adds: "That said, my general rule of thumb for buying plants is to buy from a local nursery. Stay away from buying online, as you can get unlabelled wisteria sinensis. However, if you buy from a local nursery, there a multiple people who will make sure the plant is healthy and that there are no invasive pests in the soil. Also the plant is already adjusted to the local climate."