Bright Pink Knock Out Rose Bush
knock out pruning
(Image credit: volgariver)

One thing to keep in mind about Knock Out rose bushes is that they are very quick growing rose bushes typically. They need to be kept watered and fed pretty regularly to ensure their best possible performance of both growth and bloom production. A common question with these roses is, “Do I need to prune Knock Out roses?” The short answer is that you don't need to, but they will perform better if you do some pruning. Let's look at what goes into pruning Knock Out roses.

Pruning Tips for Knock Out Roses

When it comes to pruning Knock Out rose bushes, I recommend the best time to prune Knock Out roses is in the early spring just as with any other rose bushes. 

Prune out the broken canes from the winter snows or wind whipping of the bushes. Prune out all dead canes and prune the overall bush back by about one-third of its overall height. While doing this pruning, be sure to keep an eye on the finished shape of the bush desired. This pruning in the early spring will help to bring on the strong growth and bloom production desired. 

Deadheading, or the removal of the old spent blooms, is not really needed with Knock Out rose bushes to keep them blooming. However, doing some deadheading on an occasional basis does help not only stimulate the new clusters of blooms but also overall rose bush growth. By occasional deadheading, I mean that they do not need deadheading near as often as the hybrid tea or floribunda rose bushes will. .

Timing the deadheading just right to get a grand display of blooms in time for a special event is something to be learned for each individual climate. Doing the deadheading about a month prior to a special event may put the bloom cycle in line with the event timing, again this is something to be learned for your particular area. The occasional deadheading pruning will indeed improve their overall performance in growth and bloom production.

If your Knock Out rose bushes are not performing as well as hoped for, it may well be that the frequency of watering and feeding needs to be increased. Your cycle of watering and feeding could use an adjustment of doing so four or five days earlier than you had been. 

Make changes to your cycle slowly, as big and drastic changes can also bring undesirable changes to the rose bushes performance. If you do currently deadhead occasionally or not at all, you may want to start doing the occasional deadheading or changing your cycle by a week or so sooner.

It really is all a learning process to see what cycle of care brings the best out of not only your Knock Out rose bushes, but all of your rose bushes. I recommend keeping a little garden journal for keeping track of what was done and when. Just a place to jot down a few notes; it really takes little time and goes a long long way towards helping us learn the best timing for our cycle of rose and garden care

Stan V. Griep

Stan V. Griep contributed to Gardening Know How for many years. An American Rose Society Consulting Master Rosarian in the Rocky Mountain District, he served as Gardening Know How's in-house expert on all things roses.