How To Protect Wisteria In Winter

Wisteria (Wisteria spp.) plants have long pendants of fragrant purple or white flowers that dangle in a weeping manner. They are a favorite flower for climbing over arbors, training up a wall, or growing as a conventional tree. When grown, wisteria can readily withstand harsh winters and flourishes in U.S. Department of Agriculture plant hardiness zones 4 through 9. However, young wisteria plants might not be able to withstand the first winter after planting without some protection from frost and chilly winds.

In the fall, water the wisteria plant frequently to maintain moist but not soggy soil. The plants may move nutrients from the soil and store them for the winter by receiving regular watering in the fall. When freezing conditions are predicted, water plants liberally to prevent desiccation of the leaves when the temperatures cause the moisture inside to freeze, leaving frost on the leaves.

To protect the vine’s roots from the cold throughout the winter, cover the base with a 4-inch layer of organic mulch. Anything from crushed bark mulch to dried leaves can be used. To ensure the entire root ball is insulated, keep the mulch a few inches away from the vine and cover a space that is at least 2 feet in diameter.

Wrap the main stem of the wisteria plant with a section of thin-walled plastic tubing. With a razor knife, cut the tubing lengthwise, then pry it open to allow it to fit around the wisteria stem. The plastic tubing is less expensive than using frost cloth or leftover fabric, which are typically far larger than what is required for the stem.

Create a temporary walled enclosure to safeguard the plant. Using a reciprocating saw, extend four 2-by-2-inch wooden posts by about 24 inches beyond the height of the wisteria. Using a hammer, pound the four stakes about 18 inches into the ground. Place the stakes evenly spaced around the plant, 18 inches from the stem.

Frost cloth, burlap, or another type of fabric can be used to cover the stakes. Without letting air escape around the plant’s base, the cloth must be big enough to completely cover the structure. If you require more than one piece of cloth, make sure the ends are at least six inches apart. Set up some bricks or rocks on the ground to hold the extra length in place. The inside temperature of the building stays higher than the outside temperature thanks to the heat that is radiated from the ground surrounding the plant and is trapped by the frost cloth or fabric.

In the winter, should I cover my wisteria?

Let’s start by stating that winter care for wisteria is not actually required. The tough plant wisteria can withstand a variety of harsh weather conditions. Wisteria can overwinter without additional work unless it was recently planted or was unwell. If you have the time to give a healthy wisteria a little additional care to winterize it, that’s fine, but if you don’t, don’t worry about it. Giving your wisteria a little more attention in the winter helps keep it healthy whether it was recently planted or had issues the previous year.

Mulching the plant’s base to provide the roots additional protection and clipping away any dead growth you may find on the plant are two general additional winter maintenance procedures for wisteria. You can also shape the wisteria vine with cosmetic pruning if it’s late fall or early winter (after the plant has shed its leaves but before snow has fallen).

If your wisteria has previously struggled to bloom, there’s a potential that the plant may be experiencing winter dieback, which destroys the blossom buds. If you have reason to believe this is the case, you can aid the blossom buds by wrapping the plant in burlap. This step is not necessary if your wisteria has blossomed successfully in previous years. Please keep in mind that wisteria only experiences winter dieback in extremely cold climates. There are more likely causes for your wisteria’s lack of flowering if you do not reside in an extremely cold climate.

Really, this is all that is required to care for wisteria in the winter. The wisteria will survive the winter without the extra care even if you realize that other tasks in your yard are more urgent and you do not have time to winterize it.

How can you keep wisteria from becoming sick?

Although wisteria is usually resistant to frost, it can nonetheless suffer harm from it to bloom buds and newly budding flowers. When the vine emerges from dormancy and is about to blossom, this can become a concern during late spring frosts.

Wisteria is a cold-tolerant plant that can endure frost, snow, and even extremely low temperatures in some cultivars. Wisteria, on the other hand, emerges from its latent state after the winter and starts to bloom and grow new leaves. It can be extremely harmful to the plant if a sudden cold snap causes temperatures to drop too low.

Because of this, it’s a good idea to plant your wisteria close to some wind protection, like a brick or block wall that retains heat during the day and releases it at night. To get the most sunshine, plant wisteria in a location that faces west or south.

In the first year or two of growth, your wisteria is more susceptible to frost and cold damage. Young plants might not be able to withstand these subfreezing temperatures because they are too delicate. New growth might be vulnerable to frost damage even on established plants.

If you prune your wisteria too late in the growing season, this could happen. As fresh, vulnerable vines and tendrils may develop and not have enough time to harden off before temps fall below freezing, pruning might stimulate new growth at the wrong moment. By avoiding pruning Wisteria plants at any time in the late summer or fall, you can prevent this issue.

Use plastic tubing, bubble wrap, or fabric such as burlap to shield your wisteria from late spring frosts or chilly winds. Plastic tubing is a wonderful alternative because it can be wrapped around the plant’s main vine without the need to attempt to cover a large trellis.

An additional choice is to stake the vine and hang a drop cloth or other fabric over it, covering the entire plant. Just keep in mind to take the cloth off as it warms up over the day. Before a frost, covering your plant will help protect its buds, prevent growth from being stunted, and prevent damage to the roots and vine.

How much cold can wisteria withstand?

It is well known that wisteria take a very long time to bloom. For two to three years after planting, don’t anticipate blossoms. Some readers swear by the following technique to encourage blooming:

  • To cut into part of the roots, take a shovel and drive it 8 to 10 inches into the ground approximately a foot and a half away from the main trunk of the wisteria.
  • Approximately half of the roots should be damaged for the shrub to be shocked into reproduction (flowering).
  • Don’t worry—impossible it’s to harm this unchecked, unwieldy, frequently invasive shrub!
  • The flowers of wisteria can also be impacted by chilly winter temperatures.

Native Wisteria

Consider growing a wisteria species that is indigenous to North America if you live there, such as:

  • Wisteria frutescens, also known as American wisteria, thrives in zones 5 through 9. Its original states span from Virginia to Texas, the southeast to Florida, and up into New York, Iowa, and Michigan in the north. The vine is 25 to 30 feet long, has glossy, dark-green leaves, and after the plant has begun to leaf out, develops huge, drooping clusters of lilac or purple-blue flowers. Only new wood will display the blossoms. Notably, the blossoms are typically less aromatic than those of Asian wisterias.
  • In zones 4 to 9, Kentucky wisteria (Wisteria macrostachya) flourishes. Similar to American wisteria, this late-bloomer is a native of the Southeast of the United States (it is sometimes considered a variety or subspecies of American wisteria). The Kentucky wisteria is the quickest to blossom, bearing faintly fragrant bluish-purple flowers after only two to three years of growth.
  • A gorgeous, silvery-blue cultivar of the native Kentucky wisteria called “Blue Moon” is particularly hardy. In late spring or early summer, it blooms. It can go as chilly as -40F. (-40C).

Non-Native Wisteria

  • Despite the fact that they are frequently marketed at nurseries and garden centers, Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda) are non-native, invasive species, hence we do not suggest them for North American gardens. They can reach lengths of 30 to 60 feet and are hardy in Zones 5 to 9. (and beyond in the Southern U.S.). Japanese wisteria comes in two popular kinds, including:
  • Popular plant known as “Honbeni” displays clusters of pink flowers in the late spring.
  • “Alba” (also known as “Shiro Noda”) yields beautiful clusters of snow-white flowers in the late spring.

Are Wisteria Toxic to Pets and Humans?

Yes, the wisteria plant contains lectin and wisterin, which are poisonous to people, animals, and even pets. If taken in significant quantities, these poisons can result in anything from nausea and diarrhea to death.

If pets or young children frequent the area, it is a good idea to remove the seedpods after the plant has flowered because the material is particularly concentrated in the seeds and seedpods. Unaware children or animals won’t think twice about eating as many seedpods as they can because they are not unpleasant to taste or have an instant effect. In case of ingestion, contact your neighborhood poison control center.

What should you do about wisteria frost damage?

Trim the slender, cold-blackened shoots at the tips of vines in the spring, once there is no longer a risk of frost, to at least one leaf node past the harmed area. This prevents wisteria from seeming untidy. If your wisteria is established and developing swiftly, pruning isn’t absolutely necessary because new shoots quickly cover previous damage on older plants. Additionally, injured flower buds turn black and naturally fall off the plant; you don’t need to remove them by pruning. Wisteria matures in five to ten years. Even while you might not see blooms until the plant is that old, if your Wisteria is not shielded from winter winds, a frost can harm the flower buds and stem tips, preventing your Wisteria from blooming regardless of how old it is.

Do I need to cover my wisteria against frost?

Start by purchasing a Wisteria plant in the spring that is in bloom or has flower buds on it if you want your Wisteria to bloom. Thus, you are assured that it can bloom. A small, just planted wisteria with a few tiny flowers is depicted on the left. The wisteria depicted in the video above, “Wonderful Wisteria,” was first planted in 2007 and reached a height of 3.5 meters, or about 12 feet, within 7 years. By 2018, it had completely covered the wall space at the back of the house. This is evidence of the wisteria’s vitality and the requirement for longer (and longer) ladders to prune it. It’s difficult to believe that this small plant expanded to cover an entire house wall in just ten years.

The best way to buy wisteria is as a grafted plant. Any plant grown from seed is likely to cause issues for you; while it may be less expensive, it may take a very long time to flower, possibly longer than ten years. A protrusion in the stem just above soil level in the plant pot identifies a grafted plant. The base of the Wisteria and the graft bulge can be seen if you watch the video on summer pruning Wisteria at roughly 3 minutes and 40 seconds.

Make sure to thoroughly water a fresh Wisteria plant and watch out that it doesn’t dry out in the beginning. When it’s established, it will take care of itself. I neglected to water the wisteria even throughout the 2018 drought, and it survived. Wisteria is completely hardy, however a protected area is preferred because cold can harm the racemes, or emerging flowers, (see below). Wisteria requires a lot of area and time to flourish and is simple to establish. If space is at a premium, Wisteria can be planted as a standard, which will require careful pruning, or choose a smaller variety like Domino’s or Wisteria brachybotrys.

Wisteria can be grown in a container, although the results will vary. A friend recently asked me for guidance on how to nurture a wisteria in a container after the plant failed to blossom. It bloomed magnificently the next spring after I advised taking it out of the container and replanting it in a bright location. Given the challenges in getting Wisteria to bloom, growing it in a container increases the challenge.

What color is wisteria in the winter?

Don’t panic if your wisteria begins to drop its leaves in the fall. Deciduous wisteria predominates. Winter doesn’t keep it green, but the leaves will come back in the spring.

Before dropping their leaves, some wisteria varieties put on a show of fall color as the leaves turn yellow or gold. If it’s happening in the fall, there’s typically nothing to worry about unless you’re also observing other symptoms like an insect infestation. Yellowing and dropping leaves can be signals of disease and other problems.

While Evergreen Wisteria (Millettia reticulata) is more challenging to grow, all true Wisteria are deciduous. Your Evergreen Wisteria will most likely maintain its leaves throughout the year if you have hot summers and brief, mild winters with little below freezing. This is zone 9b and higher in the US, which includes a portion of California and Arizona as well as the southern half of Florida and Texas.

Evergreen Wisteria is deciduous like regular Wisteria in more temperate regions, so you may anticipate it to go dormant for the winter and sprout new leaves in the spring. You probably won’t be able to cultivate Evergreen Wisteria in a location that is colder than USDA zone 8 because even deciduous habit cannot shield it from prolonged, bitterly cold winters.

What does a plant frost cloth do?

Frost cloth is a commercially woven fabric that is thick enough to assist retain heat from the soil and shield the plant from frost. It is light enough to allow air flow and light penetration. Use only frost cloth made for protecting plants.

Will my wisteria reseed itself?

This is quite natural, and as soon as the roots take hold, the plant will resume blossoming. Wisteria flower buds begin to form in late summer of the preceding year, just like those of many spring-flowering plants.

Do I need to remove the wisteria pods?

You can observe either smooth or fuzzy seeds if you open a wisteria seed pod. The smooth seeds are North American, whereas the fuzzy seeds are from Asian kinds. The most vigorous and potentially invasive wisteria kinds are those from Asia.

In the late summer and early fall, a healthy wisteria vine will yield seed pods. Like peas, the pods dangle from the vine. It is advisable to remove the seed pods from an established wisteria plant to preserve it blooming. If the plant is left unattended, the pods will ripen and release seeds that will shoot out many feet (approximately one meter) from the plant. The seeds shouldn’t be let to germinate unless you want a wisteria farm.