Nothing compares to the splendor of a wisteria arbor in full bloom, but sadly, many Midwestern gardeners are unable to grow these exquisite vines.
Japanese wisteria (Wisteria floribunda) and Chinese wisteria are the two varieties of wisteria that are most frequently planted in our region ( Wisteria sinensis).
Japanese wisteria is famous for its fragrant violet blooms, which are produced in clusters that range in length from 8 to 20 inches. A cluster’s individual blooms open one at a time, starting at the base.
Chinese wisteria often has clusters that are less than 12 inches long, with slightly larger individual blooms. A cluster of flowers also has a tendency to open at the same time. Chinese wisteria is less fragrant and less resilient than Japanese wisteria. Both species have cultivars that feature white blooms.
Wisteria is an aggressive twining vine that can become highly invasive in some places. Strong support is necessary for the vines to maintain their rapid growth. When wisteria is established in the right setting, it can grow up to 10 feet each year. It functions best in neutral to slightly alkaline, deep, moist, but well-drained soils.
Since the majority of gardeners are attracted to this plant for its flowers, they are very irritated by its infamous propensity to just grow greenery. This irritating issue may be caused by a variety of factors, including the plant’s immaturity, an excess of nitrogen, a deficiency in phosphorus, poor-quality plants, and an excessive amount of shadow.
Before they can start to produce flowers, Asian wisterias need to attain a certain level of maturity. In actuality, it may take the vines up to 15 years or more to bloom.
Those who have had success with wisteria frequently advise root trimming, using superphosphate, severe shoot clipping, and planting in full light. Most importantly, you should begin with high-quality plants that were grown from cuttings of plants that are known to bloom when they are still quite young. Take cuttings of the stem tips in July if you know someone who is prepared to part with a beautiful specimen. Avoid planting seedling vines since it is impossible to predict their flowering habits due to the genetic diversity of seed reproduction.
Wait until late spring or early summer to prune these vines since they develop their blossoms on last year’s wood in mid- to late May. To keep the plant manageable and regenerative, severe pruning back to three or four buds is frequently advised.
A few native species of wisteria are a little more “tame” than their Asian counterparts. These indigenous species attain flowering age earlier than Asian species because they bloom on the growth of the current season. Although they bloom slightly later in the spring, they can rebloom throughout the summer.
The 20–30 foot tall American wisteria (W. frutescens) blooms its flowers in 4-6 inch long, compact clusters. The most popular cultivar, “Amethyst Falls,” has fragrant lavender-blue blooms. Although ‘Nivea’ has longer clusters of white blossoms, it is less aromatic.
Wisteria macrostachys, which grows in Kentucky, produces flower clusters that are 8 to 12 inches long and densely covered with blossoms. Some people believe this to be an American wisteria subspecies. The hardy Minnesota cultivar “Blue Moon” has incredibly fragrant blossoms that start to develop in June and continue throughout the summer. Both ‘Aunt Dee’ and ‘Clara Mack’ have blooms that are a light lavender color.
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 can I speed up the growth of my wisteria?
Growing conditions and time are key considerations when it comes to the fast sprawl we so independently desire to see for our Wisteria. Wisteria can grow swiftly in the ideal area, but it won’t grow at all in unfavorable ones. We’ve listed our top 10 suggestions for wisteria growth below.
Tip 1: Give It Time
It’s typical for newly planted Wisteria to not grow for the first year or two. Wisteria often grows quickly, but it also lives a long time and requires time to establish itself.
If the wisteria was planted within the last two years and hasn’t yet flourished, it might just be establishing its root system. Give it another year, and there’s a strong chance that next summer it’ll start growing like crazy, so as long as the foliage is healthy, don’t panic. Wisteria occasionally takes up to five years to begin the renown quick development you read about, but it rarely does.
Tip 2: Treat Any Pests or Diseases
If your wisteria has pests or a disease, that can be preventing it from growing. A sickly wisteria may have wilted patches, yellow or brown leaves, and blotches on the leaves or stems. Examine the plant thoroughly for pests.
Scale insects, borers, aphids, honey mildew, powdery mildew, leaf spots, and crown rot can all affect wisteria. Clearing up any health issues your wisteria may have may be necessary to get it to start growing again.
Tip 3: Make Sure It Gets Plenty of Sun
The full sun is good for wisteria, especially when it is young. Older plants and some Wisteria kinds can survive partial shade, but if your plant isn’t growing, it may not be getting enough sun.
When your wisteria is already planted in the ground, this can be difficult to correct. If nearby plants are shading the wisteria, think about trimming or moving them. (If getting your Wisteria additional sun isn’t possible, you might just want to buy another one and plant it in a brighter place.) Although Wisteria doesn’t always respond well to being moved, you can also try transplanting.
Tip 4: Water
Wisteria is thirsty, especially when it is mature. Lack of water may be the cause of your wisteria’s appearance of wilting if the weather has been dry. Give it some water, but watch out not to drown it, especially if your soil doesn’t drain well. Wet feet bother Wisteria.
Tip 5: Improve Your Soil
Although wisteria isn’t very particular about its soil, it does have some demands, and the improper soil could limit its ability to develop normally. The ideal soil for growing wisteria is deep, moist, neutral to mildly acidic, neutral to mildly fertile, and well-drained.
You might try adding some compost to the soil surrounding the wisteria if your soil doesn’t drain well. Additionally, try to prevent compacting the soil by walking on it as little as possible. When you must go there, lay down mulch to help support your weight.
Apply some ferrous, ammonium, or garden sulfur to your soil if it is alkaline (the polar opposite of acidic). Through your local extension office, you can have your soil tested.
Tip 6: Fertilize (or Stop Fertilizing)
Although Wisteria doesn’t require exceptionally fertile soil, if your soil is seriously lacking in nutrients, you may need to add fertilizer to help your plant develop. This is especially true if you’ve neglected to fertilize or repotted your Wisteria plant in a few years and it’s growing in a container.
Wisteria can convert and use atmospheric nitrogen, making it nitrogen-fixing like other legumes, so it typically doesn’t require a nitrogen fertilizer. You might use an all-purpose fertilizer instead because young plants can benefit from a little extra nitrogen, which promotes foliage growth. Since bone meal mostly offers phosphorous, many gardeners use it to feed their Wisteria.
Funny thing about fertilizer is that using too much or too little can both be hazardous. If your wisteria has been receiving fertilizer but isn’t growing, consider stopping the fertilizer application and giving the soil a nice flush with lots of water. Your soil may get overly fertilized, which could harm your plants.
The subject of fertilizing wisteria is covered in its entirety in another article. Locate it here.
Tip 7: Prune
Wisteria normally needs to be pruned to prevent it from becoming too big, but a good trimming can also spur growth. Pruning promotes branching rather than a few shoots growing very long. Additionally, if you see suckers, which are little starts at the base of the plant, trimming those can encourage the wisteria to direct its energy elsewhere.
Tip 8: Give It Something to Climb
It likes to climb trellises, arbors, fences, walls, and trees. Wisteria is a twining vine. Give your wisteria something to climb up so it can get taller. If you want your Wisteria to climb on something, just make sure it’s robust and that you don’t mind it getting fully covered in vines after a few years. Learn more about teaching Wisteria to climb here.
Tip 9: Twine It In the Right Direction
Make sure you are twining your Wisteria in the correct direction if you are training it to grow around something. Chinese and American wisterias twine counterclockwise, whereas Japanese wisteria twists clockwise. Your wisteria won’t be able to develop properly if you twist it in the wrong direction.
Tip 10: Plant It In the Ground
Your wisteria might not have enough room or nutrients to thrive if it’s in a container. For wisteria to achieve that voracious growth, it needs to bury its roots deeply into the soil. Although wisteria can be grown effectively in pots, a small container may provide a challenge.
A regular nutrient replenishment is also more crucial for container soil than for garden soil. Every year, you must feed container soil with compost or fertilizer.
Make sure to use optimal techniques if you decide to move a Wisteria from a container to the garden. Wisteria is occasionally unresponsive and challenging to transplant.
Wisteria roots: are they invasive?
In order to support the massive vine, the wisteria’s root system extends out widely and dives deep. Do wisteria roots exhibit aggression? Yes, wisteria’s root system is highly aggressive. Avoid planting wisteria next to walls or walkways because of its extensive and strong root system. These are easily harmed by a wisteria’s root system.
Experts advise inserting a corrugated panel about 6 feet (1.8 m) long and several feet (1 m) broad beside the plant to redirect the roots if you find a wisteria close to a building or pathway.
How long does a wisteria take to flower?
Wisterias thrive in full light, fertile soil, and both. Of the 10 species, three are grown the most frequently: Wisteria brachybotrys, Wisteria sinensis, and Wisteria floribunda, which are native to China, Japan, and the eastern United States (silky wisteria). All three species have significant growth rates and can extend out to a maximum of 20 meters (66 feet) against a wall or around 10 meters (33 feet) in trees. Wisteria can also be trained to grow as a free-standing standard in a big container or border.
Wisterias for pergolas and arches
The Japanese wisteria (Wisteria floribunda) is best exhibited hanging down from a garden structure like a pergola or arch since it has the longest flower sprays (or racemes) of all the species. They entwine in a clockwise motion while simultaneously bearing blooms and leaves. Lilac blue blooms and racemes as long as 1.2 meters (4 feet) are produced by Wisteria floribunda f. multijuga AGM in the early summer.
Wisterias for walls
Wisteria sinensis, often known as Chinese wisteria, blooms in the springtime before the leaves do. For example, Wisteria sinensis ‘Amethyst’ AGM has violet blue blooms with a reddish flush produced in dense racemes to 30cm (1ft) long in late spring or early summer. They twine anticlockwise and the racemes are shorter so they are best presented against a wall.
Silky wisteria (Wisteria brachybotrys), which can be grown against walls or on pergolas, with downy leaves and small racemes of 10-15cm (4-6in). White flowers with center yellow markings, a strong perfume, and 10-15 cm tall sprays of wisteria brachybotrys f. albiflora ‘Shiro-kapitan’ AGM bloom in the spring and early summer.
If you want to cultivate a wisteria in a big container
It is best to choose Wisteria fructens ‘Amethyst Falls’ because of its compact habit and rich clusters of lilac-blue blooms.
Always choose a wisteria that has been developed from cuttings or by grafting when purchasing one because seed-raised wisterias flower less consistently and take longer to bloom. The graft union should be seen as a swelling close to the stem’s base. Unlike species, named cultivars are virtually always grafted. Purchase your wisteria in flower or go with a specific cultivar to avoid disappointment.
Wisterias are offered for sale as container-grown plants at garden centers and online, and you can use the RHS Find a Plant tool to locate particular cultivars.
Wisteria should ideally be planted between October and April. Wisterias grown in containers can be planted at any time of the year, but fall and winter are the easiest times to maintain. Give them healthy, well-drained soil to plant in.
Wisterias bloom best in full sun, so pick a wall or pergola that faces south or west. Although blossoming will be diminished, they will still grow in light shade.
Wisterias are robust climbers that can grow to a height and width of more than 10 meters (33 feet). You’ll need to give support in the form of wires, trellises, or outside buildings like pergolas or arches against a wall. Wisteria can also be grown up a support or taught up a tree to create a standard. A wisteria can be grown in a border or container by being trained into a standard, which reduces its vigor.
If you want to grow your wisteria in a container, you’ll need a sizable one that is at least 45 cm (18 in) in diameter and is filled with potting soil with a loam basis, like John Innes No. 3.
Feeding
Use Growmore or Fish, Blood and Bone on your wisteria in the spring at the suggested rate listed on the packet. Additionally, apply sulphate of potash at a rate of 20g per sq m (1/2 oz per sq yard) on sandy soils (which have low potassium levels). Fertilizers for flowering shrubs or roses are another option.
Feed wisteria in containers using Miracle-Gro, Phostrogen, or another comparable flowering plant food. A different option is to add controlled-release fertilizer to the compost.
Although wisteria has a reputation for being challenging to prune, this is untrue. Once you’ve made it a habit to prune your wisteria twice a year, you should be rewarded with a pleasing flower show.
When you prune regularly, you reduce the excessive, whippy growth from July and August to five to six leaves, or roughly 30 cm (1ft). This increases the possibility of blossom buds budding and permits the wood to ripen. Then, in February, trim these shoots even more to two or three buds, or around 10 cm (4 in), to tidy up the plant before the growing season starts and make it possible to observe the new flowers.
When your juvenile wisteria has completely covered a wall or other garden structure, start the routine pruning to promote flowering.
Small gardens benefit greatly from the training of wisteria as a free-standing standard in a border or container.
Wisteria can be trained to ascend into a tiny tree’s canopy, however doing so could eventually harm the tree. Pruning will be challenging if the plant develops into a huge tree, and a dense leaf canopy will affect flowering.
Increase your wisteria stocks by layering in the summer, taking softwood cuttings in the spring to mid-summer, or taking hardwood cuttings in the winter since seed-raised wisteria can take up to 20 years to flower.
Wisteria is typically propagated via grafting in professional nurseries, however layering is the simplest and most dependable technique for home gardeners.
Established wisteria can produce hanging, bean-like seedpods after a lengthy summer. While wisteria plants grown from seeds are typically of inferior quality, you might want to try growing wisteria yourself.
- After the leaves have fallen, gather the seedpods and let them ripen in an open tray.
- When the seed is ready, twist open the pod and sow it 2 cm (3/4 in) deep in seed compost.
- Before planting if the seed is dry, soak it for 24 hours.
See our commonly asked questions page for a summary of wisteria issues.
Poor flowering
Poor flowering is the most frequent issue for backyard gardeners, and it can be brought on by a variety of factors, such as:
- Young plants can take up to 20 years to flower, so acquire a plant that is already in bloom or go with a certain cultivar because they are typically grafted to avoid disappointment.
- Examine your pruning methods and timing because early and midsummer trimming will prevent the growth of flowers the next year.
- Wisteria flowers best in broad light; deep shadow produces few, if any, flowers.
- Water your wisteria during periods of drought from July to September because a lack of water during this time will influence the development of flower buds the next year.
- Flower buds may drop before opening as a result of spring frosts, which can harm or deform growing flowers.
- Applying sulphate of potash in the spring will encourage bloom production for the next year in soils that may lack potassium.
- The damage caused by pigeons or mice can be identified by torn petals or distinctive teeth marks.