One thing to keep in mind about knockout rose bushes is that they are very quick growing. A common question is “do I need to prune knockout roses?” Read here to look at what goes into pruning knockout roses.
Double Knock out roses - the least demanding rose ever. Blooms like crazy all summer long, no deadheading required. Fills up a flower bed. Plant 3 feet apart, prune in spring to keep bush size under control. Planted in full sun. Plant with blue salvia, daisies, and dianthus. I planted a climber - purple jackmanii at the base of each plant to let it grow up and through the branches in the hopes it will twine onto the deck.