Can someone give me advice on how/when to trim a wisteria vine? We have an old, large one on a trellis that is overgrown to the point that when it blossoms (about every other year) we can't see the blossoms due to the voluminous undergrowth.
Denver County Colorado pruning wisteria
Prune it hard in late winter before the leaves come out. How hard depends on your plant and the support it grows on but you might want to thin it to just a few growing points. If it's very large and too scary to do all at once, do it in thirds over a period of three years.