Mama Bear... see Miss Magnolia’s info. An older plant is identified at 10+ years... so you prune 20%. He shows you how.... very interesting and great info. Seems you trim the entire plant from the bottom (the wood) and not the stems. Thanks, MM!
Here's a bloom from the one bush we have that is old enough to bloom - we have three very young ones just planted this spring that we are looking forward to seeing in future years.