I have tried all that you recommend to get blossoms on my wisteria Lavender Falls. There are an awful lot of small stems coming off the main trunks. Could that be a problems as to why I am not getting blooms? I wonder if I should trim some small branches or stems off. At the top of the main trunk there is a large area where all the branches seem to be gathering up and down the trunk. There are small starts with leaves on them. I have never trimmed the plant in 4 years. Should I do some pruning on it in late fall or winter? Would appreciate any advice you can give me. I have added bone meal to roots, and shoved shovel around plant to cut roots a foot or so from base.
You may need to prune your vine in order to coax it to bloom. If you have not read it, you may find this article helpful: https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-blooming-problems.htm
This article will help with pruning: https://www.gardeningknowhow.com/ornamental/vines/wisteria/pruning-wisteria.htm