It doesn't get huge.......but easily twice the size of the rose, so maybe not the best choice for that pairing. A larger growing shrub may be a better support.

Be careful what you read about this clematis. Some websites (even respected ones like Bluestone Perennials) make it out to be just a colored version of sweet autumn clematis. It is NOT and shares no parentage with that clem at all - it is not a paniculata nor ternifolia! It is a complex hybrid with viticella and flammula input and is not invasive. A lovely and fragrant mid to late summer clematis but likely much too robust for a rose.

https://www.provenwinners.com/plants/clematis/sweet-summer-love-clematis-x

It gets 15x10'. That's really big. Plus it blooms on new wood, which I assume means it's a type 3. So you're supposed to chop it low every spring. You don't have to, but to get the most blooms, that's the common recommendation. Won't be fun pulling the clematis out of the rose every year.

I think it's a good idea to grow a clematis with the rose, but I would recommend getting a smaller group 2.

Thanks for the feedback. It sounds like it may be wise to proceed with caution, so I'll try planting it separate.