A spring show-stopper, wisteria plants are known for their showy collections of large, drooping clusters of flowers. Their voraciously growing, spreading vines can often be seen climbing up stone walls and even brick homes.
Wisteria, when cared for properly can grow into high-climbing vines that can spread up to 30' and live for decades!
1. Plant in a sunny spot
To promote flowering, wisteria needs a full sun location that receives at least 6 hours of direct, unfiltered sunlight daily. If planted in a shady location your plant will have good vegetative growth but will struggle to flower.
2. Choose somewhere protected
Flower buds form early in the spring because of how early the plant blooms. When choosing a location it's beneficial if you have a protected spot that will minimize damage done to the flower buds by hard spring frosts.
3. Avoid planting too close to homes or trees
While some may like the aesthetic look of wisteria climbing up the side of the house, you need to be careful as it will find its way under siding, around gutters, and into any crack and crevice possible. If planted too closely to trees it can strangle them out as the vines grow. It's best to keep them a safe distance away.
4. Provide solid support
Plants can become incredibly heavy as they grow, and are known for collapsing flimsy support structures. It's best if you have a gazebo, a trellis made out of solid wood beams, or metal pipe sunk into concrete.
5. Amend soil if poor
Wisteria are tolerant of a range of soils, but if you have really poor soil, it's best to mix compost into it before planting.
6. Space plants 10-15' apart
Because of their voracious growth, allow for plenty of room between wisteria plants. While it may look bare at first they will fill in over time.
7. Water well until roots establish
The first year after planting, make sure to water frequently as the root system is establishing. After this initial growing season you can return to a normal watering pattern of about 1" of water a week.
8. Avoid heavy nitrogen fertilizers
Nitrogen will promote vegetative growth, so it's best to fertilize with a high phosphorus fertilizer to encourage flowering. The Old Farmer's Almanac recommends applying bone meal in the spring and rock phosphorus in the fall to fertilize plants.
9. Train vines to climb
When your wisteria is young, allow 2 or 3 vines to twist together loosely and twine their way up the given support. Until the plant is mature enough to wrap around a support and stay anchored on its own, you may need to use gardening twine to secure the vines.
10. Encourage branching
The more branches the plant has, the more flowers that it can produce. As vines grow, prune off the tips to encourage side shoots to grow.
11. Prune regularly
To get prolific blooms plan on pruning your wisteria twice a year -- once in summer and once in winter. Wisteria flowers are formed on the previous year's growth so regularly pruning will encourage more branches closer to the structure. In the summer cut long shoots after the flowers have faded; in winter prune the long shoots down so they only have 3-5 buds on them. Fine Gardening has more specific instructions if needed.