Why is my wisteria not blooming? 7 Reasons

Why is my wisteria not blooming? 7 Reasons

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There are quite a few reasons your wisteria may not be blooming, from the type of plant itself through its location and growing conditions to how you’re treating it. A couple of the most common reasons are you have pruned it incorrectly and removed the flowering shoots. Too much nitrogen in the soil can also be an issue, as well as feeding them too much. Ideally, you should feed them phosphate fertilizer to encourage flowering.

To learn more about these issues in more detail, as well as other reasons your wisteria may not have flowered, read more below.

Incorrect pruning is a common cause of poor flowering

Wisteria pruned correctly to promote more flowers. If done wrong, can lead to no flowers are very few

Check that you’re pruning your wisteria at the right time of year and in the right way. Pruning it early and mid-summer disrupts the formation of flowers in the next growing season. You can literally be pruning off the shoots that will produce the flowers the following year.

What to do

Read my guide on How to prune wisteria for details on correct pruning to ensure you don’t remove flowering shoots.

Wisteria can take years to flower, especially from seed

Wisteria grown from seed can takes 10-20 years to flower
Wisteria grown from seed can takes 10-20 years to flower

Another reason that your wisteria may not blooming is that it may have been grown for seed or is simply to young. Wisteria propagated from can take up to 20, yes 20, years to bloom. That’s a really long wait for flowers. This is why most people don’t grow wisteria from seed and why they are grafted.

Even grafted wisteria, the ones usually sold in garden centres can take a year or two to flower, so maybe a little more patience is needed.

What to do

If you have grown a wisteria from seed, put it aside for the long wait and purchase another plant propagated from a cutting or a graft instead. Better to enjoy the flowers before retirement!

Wisteria need full sun, plants in shade will grow but struggle to flower

Wisteria need full sun to flower well

Wisteria love full sun, but they do grow in partial shade. This is deceptive as the plants look OK in shade but do not produce many blooms. There are also lots of different types of ‘shade’ dappled shade, shade in the afternoon. You get the point!

What to do

Try to create a sunlit area around your wisteria. Cut down any encroaching plants and remove any tall temporary structures if possible. Ideally, they need to be planted in full sun so ideal on south- and west-facing walls.

Spring frosts

If your wisteria is hit by spring frosts, the developing buds can become distorted or damaged. They may fall from the plant before the flowers have a chance to develop. This is usually rare but it has been known to happen.

What to do

Protect your wisteria plants in the winter and spring if it’s small enough. Don’t cut back the foliage in the autumn. Use horticultural fleece if necessary to wrap around the plant. Take this advise loosely as its not practical for most people but can be done for smaller, standard wisterias.

Lack of / too much nutrients

I touched on this already in the introduction. The lack of nutrients applies particularly to potassium that’s needed for flower formation. In addition or alternatively, the soil may have too much nitrogen which promotes foliage growth instead of bloom development. This can also be caused if you use a fertilsier high in nitrogen which encourage lots of leafy green growth.

What to do

Apply a fertiliser rich in potash in the spring to help along the bloom development. Tomato fertiliser applied once a month over the summer is perfect.

Lack of water

Wisteria need to be watered well in dry spells. A lack of water between July and September slows down the bud formation for blooms in the next year. This is also the case for wisteria grown in pots, they need regular watering, but if they get dry when the buds are forming, this can lead to no flowers.

What to do

Pay particular attention during dry spells to your watering schedule. Increase watering if needed.

Pigeons or mice

Look out for teeth marks on your flowers. The flowers may also appear shredded. This is due to pigeons or mice.

What to do

Discourage pigeons and mice from your garden. This is not an easy task, so you may have to live with the loss of some flowers to these pests.

I also have a guide which includes other wisteria problems as well as a guide on why your wisteria might be wilting or the leaves turning yellow. I also have a guide that discusses wisteria scale, which can lead to dieback.


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