Wisteria problem

Hi Anne,

I have something growing on my wisteria. It is hard dark brown knots on the stems and around the base of the plant. We made the plant into a tree instead of a vine and it blooms beautifully each year for about 3 years but this winter it has developed these knots and I don't know if I should cut them off or not. Will it harm the tree if I leave them on ? They look so ugly and I want to cut them off if it will not kill my wisteria. Please answer soon Thanks.

Patsy Ann
Somerville, Ala.

Anne's Response:

The problem could be crown gall, a disease that also affects rose bushes, almond, apricot, plum and walnut trees. It is difficult to control and most home owners remove and destroy the infected plant. Sometimes you can remove the infected parts of the plant and control the problem. Some growers cut out the infected areas and treat the stem with streptomycin. You may want to check with your local extension agent for a recommendation.