Why Doesn't My Wisteria Bloom
A common question we receive here at the garden center is: why doesn't my wisteria bloom?
Wisteria grown from seed can have a very long "juvenile" period before it begins to bloom. If you can, start with plants that have been grafted or started from a cutting to avoid this long wait. Also note that improper pruning or pruning in the winter or spring will prevent blooms.
Things to do to promote flowering:
Wisterias require full sun. The more sunshine you can give a wisteria the better they will perform.
Wisterias also can benefit from a good feeding of phosphorus fertilizer (superphosphate). Stay away from nitrogen fertilizers as the nitrogen will promote more leaf growth and vegetative growth but at the expense of flowers. Early spring is an ideal time to apply the superphosphate fertilizer. Follow the directions on the label and put it around the base of the plant.
If possible keep all the small tendrils pruned back throughout the summer, this will also help promote flowering.
A method of last resort is to root prune the plants by cutting the roots with a sharp shovel. Do this in late spring or early summer. Make the cuts three or four places, about twenty-four to thirty inches from the base of the plant.