Answer: There are a number of possible reasons why it might not be flowering. If it was propagated as a seedling rather than grafted (and you did not see it had bloomed prior to purchase) it may simply be biding its time and will bloom sooner or later-- eight years or so is average but 20 years is not unheard of. If it is in too much
shade or overfertilized it may not bloom. If there are buds but they do not open they are probably being frosted and thus damaged -- in some areas this happens more years than not. And if you are not pruning it correctly it may not bloom. Here are some general wisteria care instructions you may find helpful.
Good luck with your wisteria!
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