Do nothing but plant them in good free draining soil. Rosa rugosa is one of the most trouble free species roses and never suffers from blackspot or other fungal diseases.

Are these plants in leaf now? If they are, they shouldn't be as in winter they should be dormant and in the cold outside.

no leaves showing so far, just very tiny buds showing, and lots of thorns. Will Toprose provide them with enough food to give a good display. Barry.

Yes in the long term but all you will get for a few seasons is growth with just the odd flower if you are lucky. Stick with them though as when they get larger, they can flower very well. One thing though, only ever use the toprose on the surface after planting and in subsequent years. Don't put it in the planting hole and on the roots or you will just burn them.