Pruning Knockout roses, they are shrub roses, nothing could be easier, since this is a low maintenance rose bush.
Start by giving the Knockout an overall pruning and grooming to give it a pleasing and attractive shape.
When doing Knockout rose bush pruning, it's good to cut down the plant by 1/3 to 1/2, to ensure optimum flower production.
If your knockouts tend to grow very tall, you could actually be more agressive when pruning, to about a foot off the ground.
After you cut the 'Knockout' down, remove all, but the best flower-producing canes, at the base, using a pruning saw, leaving you with 4-5 good canes.
This method of pruning knockout roses will result in new canes that will grow lots of flower shoots.
The end result, is lots of rose flowers, which is what we all want.
You should then remove any canes growing inward, or crossing over another cane.
I usually remove all canes growing from the 4-5 main canes. This will result in lots of fresh new canes, which means more blooms.
Your goal is to open up the center of the bush for better air-circulation.
The picture of my backporch shows double pink Knockout roses underplanted with 'Blubird' Nemesia fruticansis perennials.
All bloom non-stop for almost 10 months every year here in Los Angeles.
I know this is more pruning than some others recommend for knockouts, but I have found that doing this every year at pruning time, results in a much better flower production that last longer for the season.
Only by experimenting with several pruning methods for the 'Knockout' roses, did I find the best method described above.
So if you want a better flower show ( and who doesn't), I recommend you follow this pruning knockout roses practice.
Now of course, you should always remove dead, damaged wood or spindly growth, any time of the year.
People are always asking, when is it time to trim knockout rose bushes?
Knockout roses are repeat-flowering shrub roses and should be pruned during the dormant season in late winter or early spring, depending on the climate zone where you live.
Another time to do some trimming, is right AFTER the first bloom flush in early summer. Followed with some Miracle Grow rose food.
This is only a light trim now to cut off spent blooms and shape it a bit so it looks good.
This early summer rose trimming, speeds up another great flower flush, but only if you fertilize also.
If you want your knockout roses to bloom even more, and look super good, deadheading is good idea, even though they are mostly self-cleaning.
Pruning Knockout roses is quite simple and very easy. The pruning instructions for Knockout roses are the same as for trimming shrub roses, since the Knockout rose bush is classified as a shrub rose.
Shrub roses have varying pruning needs, however, for most Knockout roses, pruning out and removing a few of their oldest canes each year is very beneficial, if the rose plant is vigorous and is still producing lots of new growth from it's base.