Poor pruning and too much high-nitrogen fertiliser can lead to too leafy a wisteria, with few flowers. David Hurrion offers advice on locating, pruning and feeding your wisteria, for maximum blooms.
Wisterias need to be planted in a sunny position for them to really flower well, and the new plants can take as much as five years to establish. Too much high-nitrogen fertiliser will also stimulate lots of vigorous, leafy growth. So, instead use a high-potash feed to promote flowering – and if your plant's grafted, check for suckers from below ground and remove them. But by far the biggest reason for a lack of blooms on wisteria is poor pruning. Once you're happy with the plant's basic framework, cut back all the long, current season's growth to three to four buds in July, and repeat that process when the leaves have fallen in November. This'll gradually encourage more short, flowering spurs to form on your wisteria.