Answer: Rugosas are very tough, hardy roses. You can transplant your rugosas in early fall or in very early spring, but if they are well-established plants it will be quite a job. You will need to take as large a rootball as you can manage and cut the tops way back very hard to compensate for the unavoidable root loss. (This will also reduce the number of thorns you have to avoid.) Prepare the new planting holes before you dig them up and replant immediately. Water them the day before you transplant and then be sure to water them in well; a layer of mulch is a good idea, too. If you move them this fall, be sure they are well watered up until the ground freezes. Whether you move them fall or spring, also ensure they are well watered for the entire growing season. Keep in mind, too, that they probably won't bloom for a year after moving.
The best time to cut back Rose-of-Sharon (Hibiscus syriacus), especially if you need to cut it back severely, is in late winter, but you can trim it any time. It blooms in late summer on new wood, so trimming it in mid-summer would remove the buds for the current year's blooms.
Good luck with your projects!
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