Summer ( June, July) white blooms maturing to red. Blooms occur on old wood so prune immediately after flowering.
Frost damaged, diseased or dead branches are best cut as far back to the healthy part of the branch, or main stem, as possible.
You can always snip off the overblown flowers on your oakleaf hydrangea in autumn and winter - just don’t prune when frost is in the forecast.
Hardy Zones 5 - 9