Mildewed asters

Q: My perennial asters are riddled with mildew yet again. I sprayed twice during summer and they looked well until August. Are they worth bothering with?


A: They are, but why not dump your disease-prone varieties and collect resistant ones? Try A. lateriflorus for late flowers, for example, and the exquisite blue A. frikartii ‘Mönch’ for midseason and early. A new one to me is the tall, blue A. ‘Little Carlow’ which, so far, is as clean as a whistle! All A. novae-angliae types are clean, too.