On frost-free days from mid-February, hydrangeas can be cut back before new growth appears. Depending on the type, there are certain rules that you should follow.
From March 1st, heavy cutting measures are prohibited according to the Federal Nature Conservation Act, as the breeding season for birds that could nest in the bushes begins then. In order not to accidentally cut flower buds, you should find out in advance whether pruning in spring is recommended for your hydrangeda variety.