Why won’t a reluctant wisteria bloom? There are lots of possible reasons. Bad attitude, for one. This is a vine that wants its way in the garden. Show it who’s boss–and persuade it to flower–with proper care. And prune it hard.
Despite its reputation as an invasive bully in the garden, wisteria can be finicky when it comes to performing. Buy a named variety from the nursery (rather than generic rootstock). The two most common types of Wisteria–sinensis (Chinese) and frutescens (native to American)–have varieties with blue, white, or purple flowers.
Here’s how to get your wisteria vine to flower:
Photography by Britt Willoughby Dyer.
Roll Out a Welcome Mat
Above: Plant wisteria in a protected, warm spot in full sunlight (try to get this right the first time, because it does not like to be transplanted).
Persistence Pays Off
Above: Whether you want a tree or a vine, you should prune wisteria each year to encourage it to bloom. And be patient: it can take two or three years of pruning to prompt it to bloom.
Survival Instincts
Above: Wisteria wants to bloom when it feels increased warmth from direct sunlight and when there is nothing above to climb.
Try to understand wisteria’s mentality. “Wisteria evolved where success lay in grappling up through a shaded canopy, putting lots of energy into climbing but none into blooming until it reached full sun and ‘knew’ it was at the top. There, both physical and chemical cues tell the vine ‘this is it,'” says wisteria expert Janet Macunovich of Garden A to Z.
“Choose a point that is ‘top’, train the vine to lay horizontally there and repeatedly clip off side branches that try to continue up,” says Macunovich. “This allows the top growth to develop in horizontal position and without shading foliage above.”
Mark Your Calendar
Above: Prune wisteria twice a season: in early March before it blooms and again in late summer to remove what Macunovich refers to as “whippy new growth.”
Early spring before leaves appear is the time to hard-prune wisteria. On a new plant, choose a sturdy vertical-growing vine to be the leader and remove other vertical vines. You can train the leader against a trellis if you are growing a vine or stake it if you are growing a tree.
The Mechanics
Above: On the leader, encourage horizontal branching. Remove suckers (new growth that appears in the crotch of two branches.
Encourage side branches spaced every 18 inches or so to grow horizontally from the leader. Hard-prune the vine in early spring and then cut off the season’s tangly new growth in late summer.
For more on wisteria, see:
- Wisteria: A Dangerous Beauty (Are You Tempted?)
- Paris in London: Neisha Crosland’s Planting Scheme.
- Wisteria: A Field Guide.
- Garden Design 101: Vines & Climbers.
Finally, get more ideas on how to successfully plant, grow, and care for wisteria with our Wisteria: A Field Guide.
Finally, get more ideas on how to plant, grow, and care for various vines and climbers with our Vines & Climbers: A Field Guide.