All roses can be rooted. The thing about grafting and budding is that most can be ready for sale quicker. Almost all antique and now lots of modern roses are reproduced by cuttings. All J+P New Generation roses are ownroot. Some roses really need to be grafted or budded to get going quicker in order to be ready for sale or to make them grow better like Black Magic here. On ownroot from J+P it is a very slow grower. Some roses need help. Mostly very modern roses. From my study, different rootstocks help in different climates and soil types, but don't let that stop you. You can ownroot all roses.

This list of roses that are offered as own-root roses could be a good guide. If they make a living out of these ownroot roses, they must be easy to root and grow.

Here is a link that might be useful: Own root roses at the nurseries