I just planted my knockout roses in late April. I live in Alabama, so it was just warming up at that time. It's only been two months and these things are growing like crazy...and not necessarily in a good way. Their shapes are all different. Some are very tall, and others are wide. In one bush, I have just one really tall stem that's blooming but it's about a foot taller than the other stems. So I want to trim and shape them but everything I read says wait until they are more mature before you do your first pruning...approx 2 years. I can't imagine how big these things will be if I wait 2 years! So I am just wondering if it's too early to prune them? Any advice is appreciated. Thank you!
Pruning Knockout Rose Bushes
Be sure to watch the type of rose fertilizer that you use. High nitrogen fertilizers will cause alot of growth and foliage but the blooms will be few and far between. I do shaping pruning on mine to keep them where they are supposed to be. If you do the shaping pruning often, it is far less dramatic for the rosebush. Here are some links to articles on Knockouts for you too: https://www.gardeningknowhow.com/ornamental/flowers/knockout-roses/prune-knockout-roses.htm
Are you dead heading them? Always cut off the dead bud to the stem with 5 leaves on it. My mini rainbows end did the same thing this year growing one tall stem and after all its flowers had stArted to wilt I cut it off just like I do when I dead head down to a stem with 5 leaves and it didnt hurt it none. Still growing and blooming like crazy.