I recently bought 5 white wedding hydrangeas from the southern living plant collection. They bloomed great on their first year here in zone 7. According to a YouTube channel I like to watch they should be between 4-6 feet. I would like for them to be closer to the 6 feet range vs the 4. Does anyone have these mature enough to really tell me what I can expect? I want to line a long driveway with a hydrangea hedge but if these can’t get big enough maybe I need to consider another variety.

thank you for your help!