Many bushes are grafted bushes/shrubs. This means that the top desired part of the bush or shrub is grafted onto a hardy tree root stock so that it will grow well in many climates. Some bushes and shrubs on their own root systems will not grow well in all climates. It sounds like the top desired part of your butterfly bush has died at some point and the grafted tree root stock has taken over. Thus it will not bloom again as it is no longer a butterfly bush. The best thing to do is to leave the tree if it is a pretty and hardy one. Go buy another Butterfly bush and plant it where you would like it to be and enjoy!
Answered on January 22, 2017
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