Knock Out Roses Pruning Steps: To maintain a size of 3–4’ w x 3–4’ h, Knock Out Roses should be cut back once a year to 12” high. Check your rose bush from time to time in late winter/early spring, and when you start to see new shoots growing from the canes on your rose bush, that’s a good sign that it’s time to prune. Prune Double Knock Out by taking roses for your home any time, but give the plant at least two full seasons before major annual pruning.
Time the job for late winter or early spring. Mar 01, Remove and discard any dead, crowded, crossed or rubbing branches. The goal is to open up the plant’s center and eliminate unnecessary suckers or random shoots.
Cut the rose bush back by 1/3 to 1/2 the size. With severe heavy pruning, the plant can be cut down to 18″″ depending on how large the rosh bush was. Tip: Wipe off the cutting blades of the pruner Estimated Reading Time: 4 mins. Oct 07, If the existing buds have swelled up but no new growth has appeared, it means the roses are ready to prune. The main pruning period for knockout roses is in late winter or 96%. Sep 17, Always prune in early spring when new shoots are beginning to form on the canes.
Prune to about a third of the desired final size. Knock Out roses typically triple in size after pruning. Remove dead or damaged wood when you see it. Every two or three years, remove a third of old growth to rejuvenate the shrub. Remember that your Knock Out will make flowers 16 inches above where you make your summer cuts. If you want continuous blooming, clip branches 16″ below the level where you want the next flush of flowers.
In spring I cut mine to 18″, which is 16″ below the height I want them to flower: about waist high. It is possible to leave them higher than that, depending on how big.
A resting phase is a good time to prune. About the only time not to prune is late summer and early fall, as this might encourage late growth that wouldn't harden off in time for winter. In the North, winter is not a good time to prune, but winter is just fine in the South.