Old hydrangea macrophilia pruning timetable
I have two old hydrangeas that are not blooming well or even producing much foliage. My spouse was in and out of the hospital last year with cancer so I had not pruned them. I’m going to cut them down to about 3 to 4 inches above the ground (I know they won’t bloom next year) wondering if I should do this now or in the spring. Reading different recommendations in gardening books about the timing.
Baltimore County Maryland
Hi -- It looks like you have bigleaf hydrangeas (Hydrangea macrophylla). Rejuvenation pruning for these should be done in early spring. You could prune down about one-third of the oldest stems to rejuvenate the plant over several years, each year cutting out a portion of the old branches. This way, you could still leave some flowering stems while you gradually rejuvenate the plant. Refer to our guidelines for pruning Hydrangeas. https://extension.umd.edu/hgic/topics/guide-pruning-hydrangeas
It looks like you have quite a lot of mulch around your plants. It is good to have the mulch to help retain moisture in the soil, but we recommend placing it no more than 2-3" inches deep and avoid putting it right up against the stems (to help minimize disease problems). Bigleaf hydrangeas like moist soil. Be sure to water when we have periods of drought.