When one of your plants starts turning yellow or dropping its leaves, it’s natural to worry that something might be going wrong. On the other hand, your plant might simply be deciduous and losing its leaves in preparation for winter. So what is the case with Wisteria? Is it evergreen or deciduous?
There are several species of Wisteria, including Chinese, Japanese, American, and Kentucky Wisteria, and all of them are deciduous and lose their leaves in winter. A closely related plant known as Evergreen Wisteria or Summer Wisteria is evergreen in warm climates. But despite its name, Evergreen Wisteria is not technically Wisteria and is not always evergreen.
Since one is deciduous and the other is (sometimes) evergreen, true Wisteria and Evergreen Wisteria behave differently in fall and winter. This article will go over what it means to be evergreen vs. deciduous, which types of Wisteria are deciduous, and when to prune deciduous Wisteria and Evergreen Wisteria.
The Difference between Evergreen and Deciduous Plants
In the plant world, Deciduous actually means “to fall off,” so these types of plants drop their leaves in the fall and grow new ones in spring. Some put on beautiful displays of fall color before they lose their leaves.
Evergreens are “ever green,” keeping their leaves all winter and giving us that pop of green in the winter landscape. Including evergreen and deciduous plants in the garden adds interest at different times of the year.
Is Wisteria Evergreen or Deciduous?
True Wisteria is deciduous, shedding its leaves for the winter. However, it has a close cousin known as Evergreen Wisteria, which is evergreen in some climates and deciduous in others.
The true Wisteria species commonly grown in gardens are:
- Chinese Wisteria (Wisteria sinensis)
- Japanese Wisteria (Wisteria floribunda)
- American Wisteria (Wisteria frutescens)
- Kentucky Wisteria (Wisteria macrostachya)
All of these are in the genus Wisteria, and all are deciduous.
Evergreen Wisteria – also called Summer Wisteria – is not part of the Wisteria genus but is closely related. Like Wisteria, it is part of the Millettieae tribe in the Fabaceae (pea) family. Botanists disagree about the proper name for Evergreen Wisteria, but it is usually called Millettia reticulata or Callerya reticulata. It is deciduous in most temperate climates, but in warmer regions (zones 9 and 10 in the US), it is evergreen.
Will Wisteria Die Back in Winter?
If your Wisteria starts dropping its leaves in the fall, don’t worry. Most Wisteria is deciduous. It doesn’t stay green during winter, but the leaves will grow back in spring.
Some Wisteria varieties put on a show of fall color before losing their leaves, with the leaves turning yellow or gold. While yellowing and dropping leaves can be signs of disease and other problems, if it’s happening in the fall, there’s probably nothing to worry about unless you’re also noticing other symptoms such as an insect infestation.
While all true Wisteria is deciduous, Evergreen Wisteria (Millettia reticulata) is more complicated. If you have hot summers and short winters that don’t get much below freezing, your Evergreen Wisteria will probably keep its leaves year-round. In the US, this is zone 9b and up, including the southern half of Florida and Texas as well as parts of California and Arizona.
In more temperate areas, Evergreen Wisteria is deciduous just like regular Wisteria, and you can expect it to die off for the winter and leaf out again in the spring. However, even deciduous behavior can’t protect Evergreen Wisteria from long, freezing winters, so if your climate is colder than USDA zone 8, you probably won’t be able to grow it.
When to Prune Deciduous Wisteria
The best times to prune true Wisterias are summer and late fall. Summer pruning is done after the Wisteria has finished blooming, and fall pruning should be done after the Wisteria has dropped its leaves, signaling that the plant has gone dormant for the winter. If you have mild winters, you can prune in winter instead of fall.
While Wisteria does not need to be pruned, it is a vigorous grower, so you may want to prune to keep it from outgrowing the space where it’s planted. You can prune Wisteria up to two times a year.
Pruning Wisteria serves several purposes. It keeps Wisteria to a manageable size, encourages blooming, helps to shape and train the Wisteria, and can reinvigorate older plants.
In summer, after the blooms have faded, trim the new shoots back to about six inches, leaving a few buds and a few leaves on the new growth. Wisteria flowers on the previous year’s growth, so be sure not to cut it all off unless you really need to.
You can repeat the process in late fall, removing any excess growth from the summer but leaving a few buds. This type of pruning encourages blooming and keeps Wisteria from getting unmanageably large.
If you’re looking to prune in order to shape and train your Wisteria, fall is the easiest time because, without leaves, you’ll be able to see the branch structure more easily. Cut back unwanted branches and train branches where you want them to grow. You should also remove any dead branches, although this can be done at any time of year.
You can also prune the tips off of new growth to encourage the Wisteria to branch. This can be desirable for shaping, especially if you’re training the Wisteria over a pergola or up a wall.
Annual or twice-annual pruning can keep Wisteria from getting overgrown, but if your Wisteria has gotten out of control and needs to be cut back a lot, do a hard pruning in the fall. In this case, be sure to cut the Wisteria back to a smaller size than you actually want it to be. Wisteria can grow several feet a year under the right conditions, so allow for new growth to reach the size you’re going for. Just be aware that if you prune the Wisteria back a lot, it may take a couple of years to flower again.
When to Prune Evergreen Wisteria
Like true Wisteria, Evergreen Wisteria doesn’t need to be pruned. But since it is a twining vine often used to cover arches, fences, trellises, etc., pruning it can help create the desired shape. It is also fast-growing, so you may want to prune it to keep it from growing too large.
The best time to prune Evergreen Wisteria is early spring, before the growing season. It is also acceptable to prune it later in the summer after blooming is done. Ideally, you should prune your Evergreen Wisteria once a year, unless you don’t mind it growing as large as it can and sprawling a bit.
Annual pruning to control growth can keep your Evergreen Wisteria to the size you want it. Pruning shoots near the bottom of the plant can also encourage branching there, giving you a fuller coverage of whatever the plant is climbing on. Evergreen Wisteria responds well to pruning, so don’t be afraid to cut it back if it’s getting out of control and to cut back shoots that are growing in the wrong direction.
Putting It All Together
As temperatures drop in the fall, you can expect Wisteria to lose its leaves. The plant will stay dormant for the winter and grow new leaves in the spring. The exception is Evergreen Wisteria, which will stay green all year if you live in a warm climate.
Pruning is also different for true Wisteria, which is deciduous, and Evergreen Wisteria (Millettia reticulata). Both benefit from pruning, but deciduous Wisteria is usually pruned twice a year, in summer and late fall, while Evergreen Wisteria is generally pruned in early spring.
Wisteria is hardy in the right climate, so chances are if yours is dropping leaves, or if you need to cut it back, it’s going to be ok. As long as you’re not noticing leaf drop in spring or summer, there should be nothing to worry about.