4 techniques to grow (and manage!) wisteria

Pretty but pushy, wisteria can be an awesome vine provided you’re willing to train it properly. Here are four proven techniques to help you grow and keep your wisteria tame, but still stunning.

[Image credit: iStock.com/yanjf]

Wisteria is a fast-growing climber that produces heavily-scented cascades of white or lavender blooms in late spring. Even after the blooms are spent, the foliage can form an intricate and interesting cover for walls, building and pergolas to shield them from the summer heat.

• Wisteria is also a willful beauty that can quickly outgrow its boundaries and latch onto gutters, shingles, and shutters – it can also literally pull apart all but the strongest trellis!

Unless you're willing to risk potential damage to whatever your wisteria finds in its path, your best bet is to train it to grow as an umbrella-shaped specimen in which branches emerge from a short, muscular trunk.

• Called a "standard," this tamer, free-standing form of wisteria is perfect for growing in containers.

Here are some growing tips to help keep your wisteria in check!

Regular, careful pruning not only keeps wisteria contained but also promotes next year's blooms.

Summer
Clip it after it flowers in summer by cutting off this year's long, stringy shoots to a length of no more than 15 centimetres.

• You'll want about six buds per stem you cut to remain.
• Remove any branches not needed to support the wisteria. While you're at it, remove root suckers, too.
• The flowers form on the short spurs left behind.

Winter
Prune your wisteria again in late winter, shortening the shoots to eight centimetres.

• This time trim the shoots so that they contain three buds.
• As well, snip off any side shoots emerging from the base of the trunk.
• "Suckers" left on the plant take energy away from producing flowers – hence the reason to remove them.

When it comes to planting (or placing – if it's in a container) wisteria, avoid anywhere near your house, trees, or utility lines. Before you know it, your wisteria could become a nuisance.

• It's better to train your wisteria to twine along a strong fence or tie a young vine to an upright stake and begin topping it back after it grows over a metre in height.

Only feed a young wisteria vine in springtime with a timed-release fertilizer.

• In fact, the vigour of mature plants makes fertilizing unecessary. Too many supplements may actually prevent your wisteria from blooming to its full potential.

Wisteria not blooming? One approach is to root-prune mature wisteria vines that fail to flower. By selectively cutting roots, it forces them to branch. In turn, this encourages bud formation.

• Use a spade to cut a circle a little over a metre in diameter around the trunk, slicing through any roots you encounter.

Wherever you plan to put a wisteria vine, you'll need to treat it with a heavy hand to prevent it from overtaking the wall, building or pergola to which it has attached. If you're pruning it to become a free-standing standard, you'll still need to trim it twice a year. Although it may sound like a lot of work the payoff – lush, intricate and stunning flowers – will be worth the few minutes of pruning required.