When and how do you trim a Drift rose and a Knockout rose?
The Gardener’s Answer
Both Knockout and Drift roses are some of the easiest roses to grow, and although they have different growth habits, the maintenance is the same in terms of pruning. The best time to prune your roses is late winter/early spring before new growth begins. Pruning too late in the fall may encourage tender new growth that can be damaged by early frosts. Pruning while the roses are dormant will make them less susceptible to winter injury and other potential problems.
You can certainly remove spent blooms now and any dead/diseased canes; otherwise, wait until the early spring to get your pruners out. It is always a good idea to clean up fallen plant debris. If you have not mulched this is helpful in retaining moisture and insulating the roots. As a general rule it is best to only prune one-third of the size of your roses each year. I hope this is helpful.