What Is Killing My Ninebark

physocarpi fungus, or powdery mildew, strikes. The disease commonly infects several ninebark cultivars throughout their growing range in U.S. Department of Agriculture plant hardiness zones 3 through 7. Eliminating powdery mildew requires patience. Powdery mildew affects Diabolo far less than some ninebark cultivars.

Should I cut back ninebark in the fall?

Old, dead wood also detracts from the shrub’s appearance. The plant benefits from a regular pruning in the fall after the plant goes dormant and in spring, just before blooming begins. Cut back long, leggy twigs that stick out from the top, sides and bottom of the ninebark.

What is the prettiest ninebark?

“Coppertina” ranks as the most beautiful of all ninebark shrubs, in my estimation. The name says it all — coppery-orange and bronze foliage on arching branches that shows off all season long, not just in autumn.