My practice, and that of most other experienced hydrangea growers in my area, is to keep pruning on H. macrophylla to a bare minimum. Other than the removal of any dead wood each season, they don't need or necessarily benefit from it, provided the shrubs have been properly sited to allow for unimpeded growth.

If size becomes an issue, there are a couple of ways to approach at least a temporary reduction (the plant will rapidly grow back to size) : A one time, lose a bloom season, overall whack back or the longer, 3 year rejuvenation process.

Yeah, in my case......it's got some stems that have turned into trunks (other thread). I'm going to try something new next year - maybe a gentle scrape on the outer bark on the expose large roots/trunk flare and see if it might actually invigorate/try new growth....

Got it GG. So treat it like any shrub....let the outside do it's thing, and let darwinism take it's course on the interior.

I guess there's 2 camps to this. Kinda like other shrubs. Leaves help the plant grow, so camp A says leave it alone, and just let the leaves do it's work.

Camp B is the latter, saying open it up, let light in, give it some air. Never a general consensus I suppose