They usually come back every year, so in the winter, they are dormant.

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 bushmulching.baron: 8 Federal Road, Suite 6 West Grove, PA United States. Jan 08, Proper Pruning If you want a large bush, then you should only do a light trim.

Remove the deadwood and branches, but don’t cut too deep.

Rather than simply discarding clipped canes that boast attractive flowers, stick them in a vase and put them on display in your home.

You can prune the thick sticks close to the ground. This will give a chance to new canes to sprout. More flowers Cutting back knock out rose bushes Reading Time: 4 mins.