Answer: With judicious pruning you can keep a Knockout rose somewhere around 3' tall and wide. With even more pruning, you may be able to keep it only 2' by 2'. Start by pruning it back by one third now and prune again in the spring. You can shear the plants with hedge trimmers each time it outgrows it's alloted space. You should end up with short stems but lots of leaves and hopefully, lots of flowers.
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