Answer: Rugosas as a group are noted for their hardiness and ability to withstand severe neglect. In fact, the only pruning they require is to remove dead wood and to perhaps thin a bit by removing the oldest canes to allow air circulation through the shrub. Late winter or early spring is the best time your rugosa roses. If you prune in late summer or early fall, you'll encourage new growth which will be frost tender. I'd just leave them alone for now, and plan on trimming them back in the late winter or early spring.
Best wishes with your landscape.
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