Question From: B. Cross - Colonial Beach, Virginia, United States
Q: Just noticed a solid blanket of soft white powdery substance on main branches of blue knight shrub although the rest of the plant appears extremely hardy, prolific, with many blooms. Any ideas or advice?
A: Its probably powdery mildew. It's a fungal disease.Plants are going dormant now so I would do a good cleanup of infected leaves. Next spring, when the plant leafs out spray it with a fungicide labeled for powdery mildew. Be sure to hit the lower sides of the leaves. Repeat once a month. I like an organic OMRI listed product called Actinovate. It's safe for kids, cats, dogs. and bees. Best And Happy Yardening, Nancy.