Not many people are unimpressed by the sheer abundance of the pendulous raceme flowers of the wisteria in spring. Flowering when still leafless, all attention is on those silky pastel flowers. No wonder it is one of the most popular climbers. However correct pruning increases the amount of flowers and keeps the vigorous growth in check.
All our wisterias are grafted, meaning it should flower the same year you plant it, or at least the year after. Wisterias that aren’t grafted take longer to flower, some say over 7 years.
Before planting consider how you want the plant to look eventually. For example, if you want it to hang above your door way or across a whole wall. Attach wire and eye screws to achieve your desired outcome.
When planting, make the hole twice as wide as the root ball, mix good quality compost with your soil and fill with the soil/compost mix. Add a layer of compost on top then mulch. Do not add manure. You will get more flowers if the soil is low on nitrogen. Feed a high potash fertiliser like seaweed when flowering in spring and mulch.
Wisterias are versatile if trained properly. Training is just a way of pruning a plant towards a desired outcome. Wisterias can be espaliered against a wall, grown over a pergola, arch or a wall. You can also effectively train wisterias as a standard tree because of the woody trunk they form.
pruning in winter
One benefit of pruning a wisteria in winter is you can view the woody framework and decide if any changes need to be made. Growth and flower buds are easily distinguished in late winter – growth buds are thin and pointed, flower buds plump and blunt.
When pruning always choose a clear dry day that is low in humidity to reduce the chance of disease entering through the cuts. Disinfect your secateurs and give them a sharpen. A clean cut heals quicker, the quicker the cut heals the smaller the possibility of infection. Make your cuts 1cm above a bud, angled away from the bud.
Cut the leading shoot to 75cm from a lateral branch. Prune main laterals back by one third of their length. For established wisteria cut back the laterals and side shoots pruned in summer to within two or three buds of their base. These will bear the coming season’s flowers.
Winter is also a good time to renovate a neglected wisteria. Our wisteria is scheduled to have a renovation prune next week. When renovating decide on the future appearance of your wisteria. It is best to only remove one main branch each year.
Click here to see a very informative video explaining winter pruning.
pruning in summer
A couple of months after flowering you will need to prune all the current seasons growth. You will be able to tell new seasons growth as it will be thin and whippy. Cut back laterals and side shoots to within five or six buds of the main lateral. These are the ones you’ll prune again in winter. Continue to tie in main laterals and cut them back when allotted space has been taken up.
Click here to see an informative video explaining summer pruning.
Once you’ve done a season of wisteria pruning you’ll realise how easy it is and you’ll see the difference come flowering time.