I bought more Endless Summers at the beginning of July (I cover mine, so their bloom time fills a gap for me). They were 3.5 gallon shrubs on clearance, and very scraggly when I bought them. I cut off the spent blooms and dried leaves before planting. They've come back beautifully - dark green, compact, full and also fairly full of blooms.

My established Endless Summers get quite tall with a very long internode length. I'm guessing that my beautifully-reblooming clearance plants were probably fertilized a LOT but likely also had a growth inhibitor used.

Do growers typically use growth inhibitors on hydrangeas? Can home gardeners buy the products and successfully do the same? I'd be interested in trying this on some of my Endless Summers so they'd be less leggy looking when I trim back the first bloom. I'd also consider an experiment on some hibiscus 'Summer Storm.'

Does anyone have experience with these? I did some searching and found information about B-Nine and Cycocel. I'm not sure if I could buy these as an individual (and they're not cheap), but it also sounds like this would take the correct application timing and mixture. Would appreciate any insights. Thanks!