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 kept from blooming?
A spectacular, opulent vine known as wisteria will enchant you with its heavenly blossoms year after year. However, the profusion of flowers that cover a pergola, wall, or arbor isn’t always simple to achieve. You’re not the only one who is interested in learning how to encourage your wisteria vine to produce more flowers.
You should concentrate on the surroundings and general health of the plant if you want to encourage your wisteria to blossom and generate more blooms. Make sure it receives the appropriate amount of water, sunlight, and nitrogen from the soil. Correct Wisteria pruning can also promote more blooms.
The ideal places for wisteria to grow.
According to Kirsten Coffen, a landscape architect and designer based in Maryland, “its gorgeous spring-blooming cascade of purple (or white) scented flowers is best observed when trained on a structure, such as a robust pergola.”
Such a lush, floral canopy offers delightful shade throughout the sweltering summer months. According to Irene Kalina-Jones, a landscape designer at Outside Space NYC (opens in new tab), “We plant it on rooftops in the city, training it to cover pergolas to create shade.” “But I enjoy it grown against buildings, too,” you say.
Wisteria grows best in full sun in a protected location, such as a south or west-facing facade. When planting, work in a lot of organic matter (such as compost) to ensure that the soil is rich and well-drained.
If you want to grow wisteria up a wall or the front of a house, put some effort into building a strong structure that it can climb over many years. A tensioning system of wires is possibly preferable to a wooden trellis because wood can rot. The wires must either automatically tighten as the plant gains weight or be simple for you to tighten (via turnbuckles, for instance).
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.
How frequently should wisteria be watered?
So far this growing season, we haven’t had to worry much about watering, but since rain can abruptly stop in the summer, always be prepared with the hose, watering can, and/or sprinklers.
Due to a combination of growing demand, rising heat, and increasing light, plant water requirements also increase in the summer.
Pay close attention to any new plants you may have planted this spring. Young roots are more reliant on you and your hose because they haven’t yet spread widely enough to “mine much water.
Since all of the roots are currently located close to young plants, concentrate your watering there. However, use enough water to keep the soil continually damp around the roots and slightly below them. As a result, the roots are encouraged to spread out and descend in quest of moisture.
There are two main guidelines for watering plants:
- If at all feasible, water the soil rather than the plants themselves. Leaf disease is more likely to affect wet leaves. You may have noticed recent fungus leaf spots on hydrangeas and other shrubs and perennials due to the heavy rain we’ve received.
- Early in the morning and early in the evening are the two finest times to water. After a morning watering, moist leaves quickly dry as the sun rises, whereas an early evening watering gives any wet leaves enough time to dry before dusk. Both of those times are better than midday, when evaporation loss is at its highest.
Index fingers are natural soil moisture meters that humans have and are great for determining how wet the soil is. If the soil is damp when you stick your finger a few inches into it, that is good. It’s time to water if it’s dry.
Soil moisture meters can be purchased from garden centers and catalogs if you’d want something more cutting edge. There are also digital tools with software programs that may wirelessly transmit readings of the soil’s moisture to your smartphone or computer.
Annual flowers require frequent watering since their roots are shallow, especially in the first four to six weeks after planting. When it doesn’t rain or anytime you can insert your index finger into the top few inches of soil without feeling any moisture, water them every two to three days.
Annual plants grown in pots and hanging baskets probably need water daily. A daily check is a minimum. Soak until water begins to drain through the openings.
New perennials typically require less water in the first few weeks after planting since they have deeper roots and are typically bigger than annuals. Usually, for the first four to six weeks following planting, two soaks per week are sufficient.
Unless it’s particularly hot and dry, most established perennials and groundcovers require little to no watering. In that situation, a weekly soak is beneficial.
Lilies and crocosmia, which are hardy summer bulbs that aren’t lifted every fall for winter storage, typically don’t require water unless the weather is particularly hot and dry. These perform more perennial-like tasks.
Different rules apply to tender summer bulbs like cannas, callas, gladioli, caladiums, and dahlias that you recently planted or replaced in May. Similar to what you would give a newly planted perennial, their roots still need time to develop, so they benefit from soakings roughly twice a week.
Do not water spring bulb gardens. After going dormant over the summer, flowers like tulips, daffodils, and hyacinths no longer require or desire water.
Roses thrive on soil that is consistently damp, yet they may survive with less water as well. Here, your aim might serve as a direction. Avoid watering shrub roses or soak them sometimes just during droughts if you’re aiming to grow them and/or avoid upkeep.
When it’s not raining, saturate the ground two to three times a week to get the most out of your roses.
For the first two months, soak new trees and shrubs two to three times a week, near to the rootball where the roots are. For the remainder of the first season, soak once or twice every week.
A new tree will typically require one to two gallons of water for every inch of trunk diameter at shoulder height. Apply three to five liters of water every watering to new shrubs.
Unless it has been extremely hot and dry for weeks, trees and shrubs that have been planted for at least three or four years normally won’t need water. If so, immerse deeply once a week rather than infrequently but briefly.
Perennials, groundcovers, shrubs, evergreens, trees, and vines can all be planted in containers throughout June and the entire summer.
But planting in intense sunlight, hot weather, and typically dry soil increases the “challenges” for those young plants.
Water is the major factor in managing the extra stress of summer planting. In hot, dry weather, plants lose more water than they do in spring or fall, so you’ll need to be more careful to keep the ground consistently moist.
In the heat of summer, you run the danger of harming a new plant if you allow the soil to become completely dry around it for a week or longer.
Added summertime planting advice:
- Plant throughout the evening or on a cloudy day to reduce the wilting effects of the hot, glaring sun.
- Soon after planting, mulch the area around the plants. Around annuals and perennials, one to two inches is OK; around trees and shrubs, two to three inches is preferable. Maintain a few inches of space between the mulch and the stems and trunks.
- To prevent weeds from robbing the real plants of moisture and nutrients, keep the beds clear of weeds.
Wisteria is a reasonably well-liked woody vine that attracts attention mostly for its springtime long, hanging chains of purple blossoms.
Wisteria is the queen of slow-bloomers, though. A new one frequently takes up to seven years to blossom after being planted.
There isn’t much you can do to make it go faster. If everything goes smoothly, it will bloom when it is good and ready.
The absence of sunlight may also contribute to the non-blooming of wisteria. The greatest place to grow wisterias is in full sun, or at the very least, a location with at least six hours of bright light every day.
If your wisteria used to blossom but isn’t doing as well now, it could be that the nearby trees have grown large enough to cast an excessive amount of shade.
The most common problem in non-blooming cases is fertilizer, but this is rarely the case. Wisteria roots are large and extremely effective at obtaining the required nutrients from even poor soil.
In fact, fertilizer addition, particularly the high-nitrogen kind normally found in lawn fertilizer, can prevent wisteria from flowering. A lawn that has been heavily fertilized can flood a wisteria vine with nitrogen, which is fantastic for leaf growth but not so great for flower output.
When a plant hasn’t blossomed after seven years in the ground, trimming the roots might sometimes persuade stubborn wisterias to cooperate. Root-pruning entails driving a spade through the roots at intervals of a few feet all the way around the plant and roughly a foot out from the trunk.
According to the hypothesis, because the plant “feels threatened with death,” root loss stress propels the plant into flowering (a function of reproduction).
The development that is most likely to produce flower buds will be encouraged by a good pruning carried out at the appropriate time. It would be wise to model your wisteria-pruning strategy after Longwood Gardens.
The gardeners at Longwood reduced all new shoots to a height of around six inches in July. They then restrict all development to between two and three inches during the winter, when the plants are dormant and without leaves. Normally, this leaves three or four buds, which will develop into stems and bloom in May.
Winter is also an excellent time to cut all extra branches that are encroaching on one another or causing excessive growth that is wasting energy on inefficient old wood.
Wisteria are rather long-lived and regular bloomers once they begin their first flowering cycle, especially when you perform the twice-yearly pruning.