Question: Why doesn't my wisteria bloom?
Answer: This is the most-asked question pertaining to vines. To say the least, it's a common problem. Often the exact cause will be hard to determine. Factors include shade (wisterias need full sun for best flowering), excessive nitrogen (nitrogen promotes vegetative growth at the expense of flower bud production) and pruning at the wrong time (any major pruning of wisterias should be done immediately after the blooming season).