All wisteria bloom buds are produced in the proceeding year. Severe pruning can remove the flowering buds that would produce flowers in the following spring. Vines should only be pruned back to the last 2 or 3 buds on each cane in order to leave these buds to bloom in the spring. Pruning vegetative growth can potentially help re-direct energy to blooming buds, but over pruning can remove these buds and eliminate all possibility of blooming in the following season.Some wisteria are just never prolific bloomers, however if a vine has bloomed in the past and has ceased, then these methods may help to start the plant blooming again.Sometimes, the only cure for a vine that never blooms is to replace it. Remember, wisteria thrives on neglect, often it is the vines that receive the least attention that bloom the most spectacularly.