In the spring, wisteria blooms ferociously, producing clusters of lilac-colored flowers on fresh growth that develops from spurs off the main stalks. Check out our Wisteria Growing Guide for more information on wisteria maintenance, including planting and pruning.
About Wisteria
Wisteria is a long-living vining shrub with cascades of blue to purple blossoms that, in the spring and early summer, look stunning hanging from a pergola or archway. However, this vine is known to grow fairly heavy and to grow quickly and aggressively, frequently reaching lengths of more than 30 feet. It’s advised not to put wisteria vines too close to your home since they will squirm their way into any crack or crevice they can find.
Beautifully fragrant wisteria flowers offer a feast for the senses. A brown, bean-like pod remains on the plant during the winter after flowering. There are only blooms on fresh growth.
Note: Be careful when planting wisteria! 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.
Is Wisteria an Invasive Plant?
The wisteria species Wisteria sinensis and Wisteria floribunda, which are not native to North America, are regarded as invasive in several areas. If you want to add a new wisteria to your garden, we advise choosing one of the native North American varieties, such as American wisteria (Wisteria frutescens) or Kentucky wisteria (Wisteria macrostachya), which are excellent alternatives to the Asian species.
Do you want to know how to distinguish between North American and Asian species?
While North American wisteria is not quite as aggressive in its growing tendencies and has smooth seed pods and fruits in addition to more-or-less cylindrical, bean-shaped seeds, Asian wisteria is an aggressive grower with fuzzy seed pods. Another distinction is that the flowers of American and Kentucky wisterias appear in the late spring after the plant has begun to leaf out, whereas those of Chinese wisteria do not.
When to Plant Wisteria
- Plant during the plant’s dormant season in the spring or fall.
- Wisteria can be grown from seed, although plants from seeds frequently take many years to mature and begin to bloom. It is advised to buy wisteria plants that are already established or to begin with a cutting.
Where to Plant Wisteria
- Put a plant in full sun. Even while wisteria will grow in some shade, it won’t likely bloom. Sunlight is necessary.
- Wisteria should be grown in fertile, wet, but well-draining soil.
- Wisteria will grow in most soils unless it is in bad condition, in which case you need add compost. Find out more about soil improvements and getting the soil ready for planting.
- Because wisteria grows swiftly and can easily engulf its neighbors, pick a location apart from other plants.
- Additionally, wisteria is renowned for encroaching on and infiltrating surrounding buildings like homes, garages, sheds, and so on. We highly advise against growing wisteria too near your house!
- Wisteria vines need a very strong support, like a metal or wooden trellis or pergola, to climb on. Plan carefully and use substantial materials to construct your structure because mature plants have been known to become so heavy that they destroy their supports.
Wisteria looks gorgeous growing up the side of a house, but use caution when planting it because it is a very strong vine that will get into any crack or gap!
Caring for Wisteria
- Apply a 2-inch layer of mulch and a layer of compost under the plant each spring to keep moisture in and keep weeds at bay.
- Phosphorus is often used by gardeners to promote flowering. In the spring, work a few cups of bone meal into the soil. Then, in the fall, add some rock phosphate. Study up on soil amendments.
- If you get less than an inch of rain each week, water your plants. (To determine how much rain you are receiving, set an empty food can outside and use a measuring stick to gauge the depth of the water.)
- During the summer, try pruning the out-of-control shoots every two weeks for more blooms.
Pruning Wisteria
- In the late winter, prune wisteria. Remove at least half of the growth from the previous year, leaving only a few buds on each stem.
- Also prune in the summer after customary flowering if you prefer a more formal appearance. On fresh growth, spurs from the main shoots of the wisteria develop its blossoms. Trim back every new shoot from this year to a spur, leaving no more than 6 inches of growth. So that there are no free, trailing shoots, the entire plant can be trained, roped in, and otherwise organized throughout this procedure.
- Mature plants that have been cultivated informally require little to no more pruning. However, for a plant that has been formally trained, side branches should be pruned back in the summer to 6 inches, then again in the winter to 3 buds.
- Possess you a fresh wisteria? After planting, aggressively prune the vine. Then, the next year, trim the main stem or stems to a height of 3 feet from the growth of the previous year. After the framework has grown to its full size, midsummer extension growth should be cut back to where it started that season.
How is wisteria used on a trellis?
Wisteria weighs a lot. When it is very old, its main stems may be as thick as a small tree trunk and reach a thickness of several inches. When you plant, keep the future in mind; otherwise, your wisteria will end up with a vine that is too heavy for its support.
Wisteria is typically grown on strong arbors or pergolas, up walls, or both. Start by attaching a number of 6- to 8-inch L-brackets to the support in order to secure it against a home wall. One row of brackets runs vertically up the middle of the wall at 1-foot intervals, and the other rows run horizontally at 2- to 3-foot intervals. To prevent vines from encroaching on the eaves, fasten the top row 3 feet below the eaves.
Galvanized wire should be run between the brackets. After that, attach the baby wisteria vine with string; as it grows, its stems will twine around the wire. (There is plenty of area for air circulation and growth because the wire is placed 6 to 8 inches away from the wall.)
Make sure that the support posts of the construction are at least 4 by 4 inches in size if you want to plant wisteria up an arbor or pergola. Keep the main stem firmly tied with heavy-duty garden twine until it has grown over the top of the building and is attached there. The main stem can be twined around a post or grown straight against it.
Leave the lateral branches on the main stem while the wisteria is growing, especially in the first year or two. After the plant has established healthy growth, you can start gently pinching or trimming off lateral growth at the plant’s base. As the vine climbs the post and moves along the arbor or pergola ceiling, keep trimming some of the lateral growth each year.
When the vine reaches the roof, tie it in place and direct its growth horizontally. It will be held in place as it ages by its own weight and the twining side branches. If you wish to continue lashing it down for more protection, make sure the ties aren’t girdling the branches once a year.
What kind of assistance works best for a wisteria?
For growing this most magnificent of horticultural spectacles, Alan Titchmarsh offers tips.
There are several benefits to spring arriving slowly. After a bitterly cold, rainy, and snowy winter, when army-blanket skies were the norm week after week and month after month, it is disheartening to have to wait so long for flowery joys.
Late springs, on the other hand, lessen the possibility of early development, which can frequently be severely scorched by late frosts. Due to unanticipated freezing conditions at the end of the month, a friend’s wisteria, which had put on a stunning annual display for fifty years, was dripping with depressing, grey flower trails in April last year.
Given that the buds didn’t even begin to open until the middle of April, they had high expectations for the kind of show that has become synonymous with their home this year.
How much I adore wisteria! When we got married, it graced the front wall of our humble three-up, three-down terrace house. I trained it with pride so that, during the six years we lived there, its territory grew year after year.
It was the common Chinese wisteria (W. sinensis), which for a long time was the only kind to grow in our gardens. Numerous cultivars with weird names and, in certain cases, strange colors and flower forms are available today, the majority of which are of Japanese origin.
At the Kawachi Fujien Wisteria Garden in Kitakyushu, Fukuoka, Japan, a wisteria tunnel is in full bloom.
If you’re planting a new one, make sure you like the color and blossom shape before purchasing a grafted plant because it will bloom more consistently and much earlier. A few inches above soil level, the graft union will be readily evident. There are strategies to induce blooming in older reticent plants, including those that weren’t grafted and were reproduced by layering or cuttings.
You need a sunny wall for wisteria. Giving it a wall with a north or east facing side is a waste of time. The most favored directions, where the wood will ripen most efficiently, are south and west. The pruning process itself is done twice a year. All questing growths that are required to increase the plant’s coverage should be tied in by July; all others should be cut back to around 1 foot. All sideshoots should be pruned to finger length in January. If you repeat this each year, your plant shouldn’t let you down.
Gorgeous Lodge House in Smeeth, Kent, close to Ashford, has a Georgian front covered in thick wisteria.
Wisteria is a twiner and doesn’t have sticky pads like Virginia creeper or aerial roots like ivy, so your wall will need some sort of support system. The least noticeable support is provided by strong horizontal wires attached to strong vine eyes screwed into the wall at intervals of 18in.
The likelihood of this happening can be reduced by regularly untangling the stems during winter trimming. A well-attached trellis can be used, but the snaking branches can get behind it and, as they fatten over the years, they can rip it from the wall.
Every March, you may encourage regular bloom and strong development by giving your wisteria a liberal serving of rose fertilizer, which is rich in potassium and magnesium, which assist flowers open up. If your wisteria has been pruned, nourished, and grown on a sunny wall for three or four years and still won’t bloom, consider it a failure, yank it out, and plant a grafted type that will catch up to it.
The wisteria-covered entrance to Dunsborough Park in Ripley, Surrey, is like the doorway to paradise.
The ancient standby Macrobotrys, which has flower trails that may reach a maximum length of two feet, is my personal favorite of the several types that are offered. The elegant white variety are just as striking as the lavender purple ones in the correct circumstances.
The plain W. sinensis, whose flower trails emit the most scrumptious aroma in spring sunshine, is a plant I would never avoid, especially if it were planted near a bedroom window that could be opened to let in the intoxicating scent.
Being so demanding with food and water, wisteria plants are difficult to grow successfully in pots and other containers. You can grow wisteria as a free-standing “standard” on a 5 foot bare stem if you don’t have access to a suitable home wall. It will require some support, but when I was a student at Kew Gardens, I recall enormous free-standing specimens there that were already well over a century old. They scuttled around a rusting iron structure that they had all but destroyed like boa constrictors.
To enjoy the pleasures of late spring and early summer in the company of one of the most stunning members of the plant world, all we need right now is the kind of sunny weather that was lacking earlier in the year.
Types of wisteria:
There are two varieties of wisteria: Asian and American. Although aggressive growers, Asian wisterias are well-known for their stunning blossoms. American wisterias are less aggressive and still produce beautiful blossoms. Compare the most popular wisteria varieties.
Flower color:
Wisteria comes in a range of colors, such as white, pink, and blue tones, in addition to the well-known purple blossoms. If you believe you have seen a yellow wisteria flower, it was probably a golden chain tree (Laburnum).
Foliage:
Wisterias are deciduous, which means that when the weather becomes chilly in the fall, they lose their leaves. The misunderstanding is occasionally brought on by a different vine known as evergreen wisteria (Millettia reticulata).
Avoid planting aggressive wisterias close to your home as they can cause damage and have even been known to destroy buildings.
Wisterias can be grown in full sun or partial shade, but to promote healthy bloom development, make sure the vines get at least six hours of direct sunlight everyday. If you reside in a colder area, pick a planting location that is protected because a heavy spring frost can harm the flower buds.
Create a planting hole that is the same depth as the plant and twice as wide, then level the plant with the soil surface. Because the vines will soon fill in, you should space your plants at least 10 to 15 feet apart along the support structure.
Wisterias don’t need much care once they are planted to promote healthy growth. Water frequently over the first year until the roots take hold.
After planting, wisterias could take some time to come out of dormancy and might not start to leaf until early summer. They will leaf out at the regular time the following spring, but don’t be surprised if they don’t bloom. Wisterias take three to five years to reach full maturity and may not start blooming until then.
Wisterias grow quickly and can reach heights of up to 10 feet in in one growing season. That works out well if you need to quickly cover a fence or pergola but don’t want the vines to take over your landscape. Regular pruning (once in the summer and once in the winter) not only controls wisteria’s growth but also encourages more robust flowering by creating a framework of horizontal branches and causing spurs to grow at regular intervals.
Cut back the current year’s growth to five or six leaves in July or August, or roughly two months after the plant flowers, to get rid of stray shoots and make short branches that will produce flowers the following year. Summer pruning needs to be done more frequently. Re-prune the plant in January or February while it is dormant by removing two or three buds from the growth from the previous year.
The first few years of wisteria’s growth are crucial for creating the desired framework for the plant’s development. As soon as your wisteria begins to grow, start connecting particular lateral shoots to its support structure. You should also cut down any extra growth. An aggressive pruning may be required on elder plants to promote the growth of new branches. Cut down aging branches to the main primary stem to accomplish this. The spaces will soon be filled with new side branches that can be connected back into the support structure.
Visit the Royal Horticultural Society to view a video on how to prune wisteria vines properly.