I'm in zone 6 too. I plant every mum, no matter how sorry looking I can come across. Then at Memorial day, July 4th, I cut in half to make them bushy. I propagate the part I cut off by taking off all lower leaves leaving one or two at the top. Thrust into moist dirt in a pot--or because you will have many, just into the dirt. Most take. I love mums!

I have always believed one should pinch until July 15th in our zone 4 and then leave to bloom in the fall. Plants should be really bushed out by then. Pinching any later in our area would risk losing the bloom to an early frost. Mary

Thanks so much mid tn mama and growlove. I'm a HUGE mum fan and I want to make sure that I do the right thing to encourage growth. I'll be following your advice for sure!!