How to prune Wisteria (why, when and how)
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Wisteria, fortunately, is not a difficult plant to prune, however, it is important it’s done correctly or it can lead to your Wisterias not flowering, and we have written an informative guide on this. With this fast-growing climber, you do need to establish a pruning schedule, being sure to prune twice a year at the correct time of the season so that you will be rewarded with a stunning flush of flowers the following season. We have written a guide on just how to do that and be rewarded with a wonderful display of blooms.
Deadhead your Wisteria
Though not technically a form of pruning, deadheading is the task of removing flowers from the plant when they fade. This encourages the Wisteria to produce new blooms in the same growing season.
We recommend that you deadhead your Wisteria flowers immediately after they fade and you can do this by cutting off the bloom just above any new leaves or buds on the stem.
When to prune Wisteria (and why)
You should prune Wisteria twice a year. Prune the plant in the summer, ideally between the months of July and August. This allows the wood to ripen and improves the likelihood of flower buds forming. Then prune again in the winter/early spring, in January or February because pruning at this time encourages the development of short spurs that carry the flowers in the spring and also removes any excess growth that would otherwise hide the flowers.
And always prune in dry weather.
In the first few years
The focus of your Wisteria for the first couple of years should be to establish it on the trellis or other support structure. The point here is to make sure that it attaches itself to the wires or wooden slats firmly. Prune out the very low branches, train a few strong side shoots to climb, and cut back the weaker side shoots. This will help form a good framework and don’t worry if you don’t get any flowers, it can take a couple of years for Wisterias to begin flowering.
Pruning your Wisteria in the summer
Summer pruning is done to reduce the growth, allowing light and air to reach the new young foliage. This will also help to encourage the growth that will produce the flowers.
Cut back the long, vigorous shoots to five or so buds from the base of the current season’s growth. On older, mature plants, just cut back the side shoots to the framework of strong shoots. Remove any dead or diseased wood, down to where new green wood appears. This may be all the way to the base of the stem. Prune away any suckers at the base of the plant too.
Pruning your Wisteria in the winter
The aim here is to cut away any growth from the summer that’s too long or out of place and would otherwise hide the flowers in spring. This is a good time to work on reshaping your plant, either in its height or its width, or general shape.
During the dormant season, tie in new growth over the structure to extend the main Wisteria framework. Cut any remaining stems (the same ones you pruned in the summer) back to about 30cm from the ground and reduce all side shoots to about 5cm long. This ensures that the new flowers won’t be hidden by leaves.
Pruning old Wisteria plants
Sometimes older Wisteria plants just wear themselves out and you need to hard prune these. You can do this by cutting back the old branches to the central stem. Find new strong side branches to then tie in and start to create a new framework made from younger branches. Hard pruning stimulates growth in the Wisteria and will encourage lots of new growth. It’s also advisable not to feed your Wisteria after a hard prune because it can encourage too much green foliage.