Your roses will already be somewhat stressed due to the heat.

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.

However, I did not give up and kept trying with different varieties and used the best fertilizers, and yet the results were the same.

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.

Follow these simple steps to cut back your Knock Out Roses:Location: 8 Federal Road, Suite 6 West Grove, PA United States. Jan 08, The best time to prune all types of roses is either in late winters or in early spring. This is the time when new growth starts. Fall is not a good time for pruning, as this could lead to the death of the plant.

These are low-maintenance bushes and can grow on a variety of soils and in a variety of weather.

When it comes to cutting back a knockout rose plant, there are Estimated Reading Time: 4 mins. 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 stumpchopping.barted Reading Time: 5 mins.