I am talking about Rosa Rugosa, rather than hybrid tea and similar grafted
Rosa Rugosa is the rose with millions of tiny spines all over the stems, and either white or magenta/pink flowers. This is the rose frequently used to make hedges. It also has attractive bright red rose hips in the autumn.
This rose throws suckers up and spreads anyway, but if you want more plants then take cuttings now.
Cut off a few hard wood stems. Trim away any green shoots, flowers and rose hips. Cut the stems into lengths about 8-12 inches long.
Stick them into a container of used compost so that half their length is buried.
Keep pink and white rose stems separate, so you will know what colour flowers to expect from each rooted cutting next year.
These roses make a superb boundary hedge. I have one growing in the 12 inch wide gravel bed alongside the fence down my drive. I want them all the way up the drive, about 60 feet, so I took a lot of cuttings.
I also use them as a visual barrier to separate the compost heap area from the rest of the garden