I've read that I should cut my Annabelles down to about 12" in the fall and then they will get sturdier stems and larger flower heads next season. Is this true? I've never cut mine and they are 15+ years old.
Livingston County Michigan annabelle hydrangea pruning
Yes, many gardeners prune them to about 12 inches in late fall, winter or very early spring. If you are happy with your shrubs as they are, you need not change anything you are doing. Annabelle blooms on the current season growth. So, they are pruned late fall to early spring, before any new growth starts for the spring. Hydrangea arborescens ‘Annabelle’ can be pruned/cut right to the ground, but leaving a basic framework of 4 to 6 major stems, 12” to 15” tall does help to create a more stable structure for the new growth.
Here are a couple references for you—-
This youtube video is from a commercial site. MSU Extension does not endorse this site, but this video clearly explains pruning Annabelles—-
Thank you for using our service.
One other clarification- the “4-6 stems” means
per square foot or so, if you have a large hedge of many Annabelles.