I have 2 wisterias and they are covered in blooms that are not yet in flower (probably due to current weather conditions) but the leaves are coming out now. This happened last year as well. I thought that the leaves would not appear until after the flowers were in full bloom. When the leaves come first, they cover the blooms and the overall effect is not so good.
Certified GKH Gardening Expert
If you notice beautiful purple blooms prior to foliage growth, then you probably have a Chinese wisteria. This type forms flower buds on previous year’s wood. Therefore, it commonly blooms before the plant actually leafs out. Japanese wisteria blooms after the plant has sprouted leaves.