Wisteria is loaded with blooms but they are very small--about the size of a large lemon. Other years they were very big.
Certified GKH Gardening Expert
Try to limit the nitrogen and offset it with some phosphorus, like bone meal, to help promote more lush blooms. Here is more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm