I read your 2012 article on wisteria pruning before I gave my wisteria a hard cutting this past weekend. I even cut out most of the many suckers at the base of the plant. I hope I didn’t overdo it. I still have to work on the horizontal branches.
The second cutting is in winter. In Canada, specifically Oakville, Ontario, which months are we referring to?
Thank you for posing your question to the Toronto Master Gardeners. How lucky you are to have such a lovely Wisteria vine that has stayed blooming for 18 years.
Wisteria’s come in four major kinds, and the different varieties have different pruning regimes. Since you are planning on pruning twice a year, I am presuming that you have either the Japanese or Chinese wisteria.
- Wisteria floribunda Japanese wisteria
- Wisteria sinensis Chinese wisteria
- Wisteria fructescens American wisteria — flowers on new growth
- Wisteria macrostachy Kentucky wisteria
The Toronto Master Gardeners answered a similar question more recently, on September 23, 2019. They suggested:
For pruning advice, both to control size and to encourage bloom, take a look at the Toronto Master Gardeners’ guide How to Get Wisteria to Bloom.
The Gardener’s guide does not specify the month in winter to do the second pruning, but suggests that it should be done in late winter. My suggestion to you is to find a warmish day in February, when the soil is still frozen so you will not compact the soil while doing your pruning.
For another similar perspective and additional advice, the Farmer’s Almanac suggests the following when it comes to pruning:
“Pruning is the secret to good flowering, as wisteria only bloom on new wood.
- Prune wisteria in late winter. Remove at least half of the prior year’s growth, leaving just a few buds per stem.
- If you want a more formal appearance, prune again during summer, after traditional flowering.
- For more blooms, try cutting back the rampant shoots every two weeks during the summer.”