Too much nitrogen is most likely the cause of your wisteria’s failure to blossom. Too much nitrogen will cause wisteria plants to generate a lot of foliage but very few, if any, flowers.
The habitat in which wisteria is growing is another cause of blooming issues. When wisteria vines are stressed, they may not flower but instead sprout leaves in the absence of full sun or sufficient drainage.
How can I make my wisteria bloom?
The best way to get a wisteria to bloom
- Ensure full sun. Ensure that the plant is getting enough sunshine.
- In the spring, prune.
- Re-prune in the winter.
- Trim the roots of the tree.
- Around the trunk, cut a ring.
- Include fertilizer.
What can I give my wisteria to encourage blooming?
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.
Other problems
A mature, seemingly robust wisteria will occasionally pass away and be replaced by a new, healthy branch emerging from the ground. Failure of the wisteria graft may be the reason of this.
Wisteria is sensitive to both of the fungi that cause phytophthora root rot and honey fungus, which are less frequent causes of failure.
Unusual brown blotches and marks on the leaves, typically with a yellow edge, may be a sign that a fungus has infected them. Viruses can also harm wisteria and powdery mildew.
Infestations of scale and, less frequently, wisteria scale can affect wisterias.
While we hope this information may be useful to you, we always advise reading the labels on your plants that provide care instructions.
Do coffee grounds work well with wisteria?
The garden can employ coffee grounds in a variety of ways. Although the impact is typically quite minimal, they can make the soil more acidic. Coffee grounds can enhance soil texture and drainage much like any other organic material. If you’re going to incorporate them into the soil, it’s better to compost them first. The compost pile benefits greatly from the addition of coffee grinds.
Wisteria doesn’t prefer acid, thus it typically doesn’t require a boost in acidity from coffee grinds. The optimal soil for wisteria is neutral to slightly acidic, therefore if your soil is alkaline to begin with, you only need to make it more acidic for wisteria.
Coffee grinds aren’t the best approach to lower the pH if your soil is alkaline, but they occasionally work. Although coffee beans are acidic, when you brew them, most of the acid is removed, leaving less acid in the grounds. Additionally, as the coffee grounds degrade, their pH does not remain acidic.
Purchase some garden sulfur or ferrous sulfate if your soil is too alkaline for wisteria. Applying coffee grounds might occasionally be helpful, but it probably won’t make much of a difference.
TL;DR: Spreading coffee grounds around your Wisteria is typically not beneficial.
Why is my wisteria acting up?
There are numerous reasons why this symptom could exist. Root conditions like honey fungus and Phytophthora root rot can affect wisteria. Vine weevil grubs, in particular, can harm the roots of container plants.
Can you fully prune the wisteria?
If the wisteria plant has a lot of dry, old branches and appears to be highly out of shape, it can be severely pruned back.
In order to renovate the plant, it is occasionally necessary to remove every branch, all the way to the main stem or even to the ground. Your wisterias will be inspired to grow new, robust branches as a result of this severe trimming.
McKenzie cautions that while the growth will be of much superior quality, the wisteria may not blossom for two or three years following a hard cut back.
A new pergola or arch can be created by “hard pruning” in addition to retraining the plant.
Year 1
Consider trimming the main leader of your wisteria once it has been planted, to a robust leaf bud around 3 feet from the ground. Next, prune any extra side shoots to encourage the development of a strong leader.
Set your new leader in place, then pick out some sturdy side shoots and secure them at a 45-degree angle. Your lateral branches will be formed from these shoots. Trim them back to 3–4 leaf buds as they expand. Future seasons’ flowering spur formation will be aided by this.
No matter when you planted your wisteria, check on it again the following winter after it has finished its first full growing season and is completely barren of leaves and blooms. If we’re lucky enough to have one, pick a sunny or dry day to do winter trimming.
The first year might be difficult; it may seem counter-intuitive to severely prune and keep your young plant small. But for the growth of a solid structure and a nice set of flowering spurs, this is very necessary.
Year 2
Keep tying and directing your main leader (it is OK to have two leaders if it makes sense for your situation). Choose a second (and/or third) pair of shoots to develop into lateral branches as your leader grows, and tie them in roughly parallel to the first set of laterals from the prior season.
You might now be able to detect basal growth—young shoots that are erupting from the base. An immediate and continuous cut with a clean, flush cut against the trunk is required to remove them. If they are sprouting up right at the base of the trunk, you can either dig a little bit around them and make a shallow incision beneath the soil surface, or you can softly cut them with a spade.
Also removed should be any sturdy tertiary shoots that may have sprung from the lateral branches and were expanding swiftly outside of the framework you had built.
Keep an eye on the plant throughout Year 2’s summer to prevent excessive growth until you begin to fill the plant’s designated space.
Year 3
Continue the above-mentioned procedures after your plant is well-established (from year 3 on).
Most of the side shoots from this year should be pruned back to 5–6 buds in the summer, about two months after flowering.
Cut these same branches back even more in the winter, to one or two base buds. This will aid in bloom production for the upcoming season. If the wisteria has grown to the proper height, you may also trim any leaders back by around a third. In addition to managing overall size, this keeps the wood strong and orderly rather than weak and disorganized.
Renovating an older, overgrown wisteria
If you have an older, overgrown wisteria, heavily thin it out in the summer, but try to avoid making significant cuts (about two fingers to wrist width), as they are best done in the winter.
The greatest time to examine the structure and potential of older, neglected specimens is frequently during the winter. You can gradually train a wisteria back into a regulated and free-flowering form by following the guidelines mentioned above.
Wisterias may resist severe renovation trimming, but this may cause a one- to two-year delay in blossoming. Your wisteria will ultimately bloom once again, so don’t worry.
If a wisteria needs to be completely removed because you need to undertake construction around it, cut it at the base to prevent soil from compacting around the trunk. If the plant was exceptionally vigorous, new shoots will often emerge from the old root system. Again, it will take some time before it starts to bloom again, but thanks to the established root system, recovery time should be rather short.
Although it does need some maintenance, wisteria can be a highly rewarding plant with a commanding presence in the garden. Given that wisteria has a tremendous potential for growth, the possibilities for training it into unusual forms or over structures will allow you to build a true garden treasure that you can enjoy for years and years as you get to know your plant’s structure better over time.