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.
Wisteria can endure 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.
How much cold can wisteria withstand?
In terms of their resistance to cold, the many species of wisteria that are found throughout the country differ slightly from one another. For colder climates, some types are more suitable than others. All Wisteria, however, prefers milder climates and does best in full sunlight. Below USDA zones four or five, the majority of wisteria vines are not cold hardy.
Chinese and American wisteria are cold hardy to zone 5, whereas Japanese wisteria is hardy to zone 4. Among the variants, Kentucky Wisteria and “Zone 3-hardy Summer Cascade, however these kinds are far less widespread than the well-liked Japanese and Chinese varieties. Among the Kentucky Wisteria cultivars, the variation called as “Blue Moon can withstand temperatures of -40F.
In the United States, a few varieties of wisteria grow natively in the wild. In USDA zones five to nine, American Wisteria (Wisteria frutescens) naturally flourishes. Southeast Florida, up to New York and Michigan, and it may thrive in a variety of settings.
The native Kentucky wisteria (Wisteria macrostachya), which thrives in USDA zones four to nine, can be found from the southeast of the country up through its northern states.
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).
Can wisteria survive a cold climate?
Wisteria vines can withstand a wide range of environmental factors, but the majority of types struggle in zones below USDA 4 to 5. Wisteria plants in Zone 3 were a bit of a pipe dream because these beloved plants of temperate climates often died during the cold, prolonged winters. Zones 3 to 9 are favorable for Kentucky wisteria, a chance hybrid that can be found in the swampy regions of south central United States from Louisiana and Texas north to Kentucky, Illinois, Missouri, and Oklahoma. In the cooler location, it even consistently produces flowers.
Japanese and Chinese wisteria are the two varieties grown most frequently. Chinese wisteria is appropriate down to zone 5, whereas Japanese wisteria is a little more hardy and thrives in zone 4. The Kentucky wisteria is descended from the American wisteria, Wisteria frutescens.
The plants naturally grow in highland thickets, riverbanks, and marshy woodlands. While Kentucky wisteria may flourish as low as zone 3, American wisteria is hardy only to zone 5. Wisteria can be grown well in zone 3 thanks to a number of novel cultivars that have been released. Compared to its Asian counterparts, Kentucky wisteria is less pushy and more well-mannered. Even after severe winters, it regularly blooms in the spring with slightly smaller flowers.
In USDA zone 3, Wisteria macrostachya, another plant, has also demonstrated its dependability. It is marketed under the name “Summer Cascade.”
The best wisteria vines for zone 3 are Kentucky wisteria plants. Even a few cultivars are available for selection.
A Minnesotan cultivar named “Blue Moon” sports tiny, fragrant clusters of periwinkle blue flowers. In June, vines can reach lengths of 15 to 25 feet and bear racemes of fragrant, pea-like blooms that are 6 to 12 inches long. These zone 3 wisteria bushes then develop 4–5 inch long, velvety, soft pods. The plant’s delicate, pinnate, dark green leaves on twining stalks only add to its allure.
The aforementioned “Summer Cascade” has racemes of delicate lavender blooms that are 10 to 12 inches long. Other varieties include “Clara Mack,” which has white blooms, and “Aunt Dee,” which has lovely antique lilac flowers.
Wisteria does it grow in the North?
In the spring, wisteria blooms ferociously, producing clusters of lilac-colored flowers on fresh growth that develops from spurs off the main stalks. See more about caring for wisteria, from planting to pruning, in our Wisteria Growing Guide.
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.
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.