Pruning wisteria

by Adam Pasco

For the past few weeks I've been enjoying the wonderful sight of my weeping wisteria coming into flower.

Wisteria flowersFor the past few weeks I've been enjoying the wonderful sight of my weeping wisteria coming into flower. I've grown it in a large terracotta pot, and as the compact branch framework has developed over the years it's produced more and more blooms.

I'm happy we haven't experienced any harsh late frosts. These could prove the kiss of death for delicate wisteria flowers, so I'm keeping my fingers crossed that May treats me kindly with mild weather. Frost is a damaging force, prematurely ruining flower displays on so many trees and shrubs, such as pieris. But with blossom on many fruit trees now at its peak, frost can kill flowers before bees have had a chance to pollinate them. When this happens the blossom will fall without developing any fruit.

By keeping an eye on the weather forecast, I can get outside and throw a large sheet of white fleece over my wisteria, plum and cordon apples to protect the flowers when frost is due. It's not much of an effort, but it will reward me with longer flowering displays, and fruit to enjoy later this year. It's essential to prune wisteria twice a year. Once in the summer, shortening long, wispy new shoots to about 20cm (8in), and again in winter, pruning the same shoots further to roughly 5-7.5cm (2-3in). This pruning sequence promotes the development of flowering spurs along the main branches, and the effort really is worth making. Fingers crossed for a frost-free forecast!

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Gardeners' World Web User 04/05/2009 at 14:43

We started wisteria growing up a post to the top of our pergola and it is just now reaching the canopy to start spreading. I haven't pruned it at all because I don't want branching below the canopy. This should work, shouldn't it? (Might take longer to get lots of blooms, I realize.)

Gardeners' World Web User 04/05/2009 at 17:24

I'm interested in growing a wisteria in a large pot. Please can you tell me how large a container your wisteria is in, and how tall it is? Thanks

Gardeners' World Web User 05/05/2009 at 06:57

Kylee - I have two rather small potted wisteria that I too would like to grow over my pergola, how large were yours? Mine hardly seem to have grown at all over the last year. At this rate reaching the canopy will take 10 years!

Gardeners' World Web User 07/05/2009 at 15:33

I have recently planted a wisteria in my garden, it is only about a metre high how high should it grow before I need to prune it.

Gardeners' World Web User 07/05/2009 at 16:11

Reply to chillipasta: Pruning and training depends on how you want to grow your wisteria. Most people want to train a wisteria to cover a wall or pergola, so you need to train the main leading shoot in the desired direction. As side shoots develop these can be tied in to produce more of the main framework. Future summer and winter pruning aims to shorten side shoots developing from these main stems of the framework, encouraging flower buds to form at the base of every sideshoot. Just picture a long horizontal stem trained along the wall of your house with flowers cascading down from in at regular intervals along the entire length.

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