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.
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.
How should wisteria be cultivated?
Wisteria should be grown next to a strong wall, such as the front of a home, in moist but well-drained soil, ideally facing south or west. Both in February and August, prune. To promote flowers in the spring, fertilize with a high potash fertilizer.
Does wisteria need assistance when climbing?
Wisteria can be trained to grow in a variety of ways, but it will always need some sort of support when climbing. Wisteria is renowned for covering whole surfaces and enticing us with full walls of fragrant blossoms.
Although this plant can climb big structures like your neighborhood Spiderman, it is actually incredibly adaptable. They can also reproduce by dropping seeds, and their roots have the capacity to create suckers far from the parent plant. Wisteria, though, will climb everything within reach.
How is wisteria fastened to a wall?
on a wall. Wisteria should be trained as an espalier with horizontal support wires (3mm galvanized steel) spaced 30 cm (1 ft) apart for the best results when grown against a wall. Plants will develop a robust spur system with time and twice-yearly trimming.
Can wisteria grow on a fence?
Wisteria sinensis or W. floribunda are the two species that we grow the most frequently. The former Chinese wisteria bears its flowers prior to the development of its leaves. The blossoms of the Japanese wisteria floribunda develop simultaneously with its foliage. These details have a significant impact on the species you should choose to raise. W. sinensis thrives on vertical surfaces (house walls, fences, trellises), where its bare blossoms will be best seen. It is preferable for W. floribunda to grow up and over strong arches, arbours, and pergolas. As a result, the longer racemes (bunches of flowers) can hang down and be completely free of the leaves.
How to plant wisteria
Wisterias grow best in soil that is fertile but well-drained. Even though they perform best in direct sunlight, they can tolerate little shade. They can be grown in big containers. To prevent a “rain shadow,” make sure plants are 30–40 cm away from the base when growing up a vertical surface (the dry, shaded area closest to the base of walls and fences). Back the shoot up toward the ground.
Wisteria can be grown into a free-standing specimen; more on that later.
Training wisteria as a climber
When preparing Wisteria to climb, there are only four guidelines to remember:
- In July or August, reduce the whippy shoots from the current year to just five or six leaves. This improves bud formation and speeds up wood ripening by increasing air movement and light penetration through the leaf.
- In January or February, perform a second cut, only removing two or three buds.
- Strong, taut training wires positioned horizontally along a wall or fence are used to train desired shoots. Use soft twine to secure shoots to these wires.
- If it’s necessary to remove old, diseased, or unwanted shoots, wisteria will react nicely to hard pruning. However, be cautious since shoots entwine around one another; you don’t want to unintentionally harm good, productive growth.
Training wisteria as a free-standing specimen
In your garden, grow a few free-standing wisterias for something a little different.
- Plant a wisteria with a single stem next to a reliable support (1.5m or more). The single stem should be tied in and let to extend all the way to the support’s top.
- In the first spring after it has reached the peak, cut off the single stem tip.
- Trim the upper side shoots to 15 to 30 cm in length and remove the lower side shoots. The plant now has a sturdy “head” from which to grow.
- August is the time to prune August shoots back to seven leaves once the head has gotten sufficiently woody.
- To keep your shape, trim any old, undesirable head shoots in the winter.
- To reveal flower racemes, trim March shoots back to 2.5 cm of their bases.
How is wisteria made to climb?
My initial apartment search in Brooklyn led me to a one bedroom on a peaceful, tree-lined street. The apartment wasn’t particularly noteworthy, but the structure was: The entire brownstone, windows and all, was covered in an impenetrable mass of wisteria. Some strong wisteria vines, which may grow 10 feet or more in a single season, can easily cover a three-story building. Despite its rambunctious nature, a wisteria in full blossom is one of the most beautiful views.
Wisteria may happily twine, climb, and sprawl over anything in its path for a very long time without any pruning. But a trimming routine becomes an essential task for the gardener who has a small yard and wants to enjoy more obvious and many wisteria flowers. Plan on pruning at least twice a year (once in the summer and once in the winter) for best results. Understanding how the vine develops will also help you succeed.
Not everyone prefers to live without windows, but no one needs to if they plan ahead and make a commitment to routine pruning.
Summer: Cut the long shoots after flowers fade
Since wisteria flowers grow on the growth from the previous year, pruning wisterias twice a year not only keeps them in controllable proportions but also develops a network of short branches close to the building so you can more readily enjoy the blooms. Simply cut the long branches from the current year’s growth back to 6 inches in length in the early summer after the vines have flowered to achieve this. Pruning away root suckers, especially on grafted kinds, and totally removing any branches not required for the main framework of the plant should also be done at this time. Depending on how much time you have and how tidy you want your vine to look, you could choose to prune this way once or more regularly during the summer. Remember that wisteria seedpods are ornamental to many gardeners, so you might wish to leave some wasted blossoms remain.
Design Tip
For winter interest, some seedpods may be left on the vine, but if you bring them inside, high temperatures will force them to explode. The pea-shaped fruit was once utilized by a friend as part of a winter arrangement. The following morning, she discovered her cat hiding in a corner from the flying seeds.
Winter: Prune long shoots down to three or five buds
Trim the long stems that have sprouted after the summer trimming to three to five buds in the late winter. Remove any undesired long shoots from the previous season as well; they will be easier to spot now that the framework is leafless.
To focus energy on flower production rather than vegetative development, even short branches should be pruned to three to five buds.
Why your wisteria may not bloom
Wisterias are infamous for not blooming. Make sure these fundamental cultural prerequisites are satisfied before attempting severe measures.
The decision to go with a seed-grown plant rather than a grafted plant is the most frequent cause of a lack of flowers. While seed-grown vines may take up to seven years before flowering, grafted plants normally blossom within three years.
High winds and late frosts can harm flower buds, particularly those of Wisteria sinensis. Wisteria, on the other hand, blooms best following years with hot summers.
Avoid fertilizer with a high nitrogen content. Wisteria fixes nitrogen in the soil like other legumes do. A surplus of nitrogen might result in poor flowering and excessive leaf growth.
Training a new wisteria on a pergola
The plant’s strength allows it to adapt to various forms. Wisteria can be trained against a structure or lattice, molded into a shrub or standard, or planted on a pergola or arbor. Because of its long blossoms, which dangle dramatically through the top of pergolas and arbors, wisteria floribunda is a popular choice. Since it grows so quickly, like other wisteria species, only one plant is typically required to completely cover a structure. However, placing two vines at the opposite ends of a structure provides it aesthetic balance and allows a gardener to showcase two different cultivars on the same structure.
Planning is essential when training wisteria to grow on a pergola or arbor. These constructions must be fashioned of a sturdy, weather-resistant material, such as cedar, and properly anchored in the ground with concrete footings in order to be used effectively. Don’t be scared to overbuild a pergola or arbor because wisteria is notorious for tearing down its supports. I suggest using at least 24 lumber for the crosspieces and 44 lumber for the posts.
Allow two or three young shoots to knot loosely around each other and the post as they grow to start training a new plant onto a pergola or arbor. Since the woody stems grow gnarled and attractive as they mature, this will help give interest to the plant’s structure. As they climb, the young shoots need to be fastened to the post. To do this, fasten a 14-gauge galvanized (or comparable) wire to the post using eye hooks spaced roughly 18 inches apart (or on all four sides for extra support). Use gardening twine to secure the shoots to the wire as they develop. As they develop, give them some breathing room to develop a more attractive habit and avoid having them mature and put a lot of stress on the framework.
The shoots should be headed back (their tips should be pruned) once they have reached the top of the arbor to encourage side shoots that will spread across the tops of the supports and bear flowers. The training ties on the post will no longer be required as the plant matures and becomes more stable across the top of the structure. In order to keep the plant from becoming girdled as it grows, it is a good idea to remove them.