My Wisteria has developed powdery mildew spots in a three separate
places (my wisteria and clematis cover a 23' patio pergola. I believe
it came from some sweet pea that I cut out as soon as I saw the mildew.
I'm worried about my wisteria, though. Even though it's already
bloomed, I usually have a small second blooming. In addition, I'm
afraid it'll spread to the clematis that I have growing in with the
wisteria. Is there any way to stop it/prevent it from spreading?