When is the best time to prune beach roses?
Question:
When is the best time to prune beach roses? We have a row of one and two-year-old bushes which have put out a lot of suckers and tall new growth. We are hoping for a wild-looking hedge. Also, the hips all turn black a short time after turning red.
Answer:
MOFGA (the Maine Organic Farmer and Gardener Association) recommends minimal pruning when growing beach rose (Rosa rugosa), so I would advise just conservatively following standard woody plant maintenance pruning advice. That is, wait until late winter/early spring, concentrate first on simply removing dead or damaged plant tissue (either to the ground, or back to a living, vigorous portion), then problematic limbs (e.g. rubbing against another), and then heading back the tall growth and thinning out any weak suckers until you have the shape you like. Never take out more than 1/3 or so of the total healthy tissue per season, to avoid damaging the plant.
As far as the hips go, the fruit will deteriorate naturally on the plant, so you may just be seeing normal senescence (i.e., planned cell death in plants). But if it appears pathogenic in some way–e.g., fuzzy growth on the hips, gnarled leaves, etc.–you could submit photos to the UMaine Plant Disease Diagnostic Lab for evaluation. There is small fee for their service, but you would have confirmation of any pathogens present. However, as long as the plants seem otherwise healthy, you could always wait and see if they behave differently next year.
Happy gardening.