Wisteria is growing over a pergola in sunny position. Has flowered and grown well in previous years. This year some flowers but now no leaf growth. Normally, we would be fighting our way through the growth. No sign of galls on trunk.
Large Wisteria Has Grown Well but Now Not Growing
Certified GKH Gardening Expert
I would try giving it some fertilizer as well as making sure that it has enough water.
As a precaution, treat the plant with both a pesticide and a fungicide. There are many, many things that could be causing this and doing all of these things will address a large majority of them.