trimming and shaping Diablo Ninebark
When can these Ninebark be trimmed? We would like to control the size but would trimming and shaping now, mid-summer, be harmful to the plants?
Washington County Minnesota
Ninebark should be pruned while dormant, preferably late winter, such as the end of March. While pruning now is not ideal, some light pruning can be done. But don't wait until late summer. Pruning then encourages new growth just when the plant should be shutting down for winter. Here is a good pruning guide: