Rose Beds

Answering the question depends a lot on the climate you are in. If you are in a place with a lot of rain, the rocks might help the ground retain too much moisture and cause root rot. If you're in a very warm climate, the rocks might absorb a lot of the day's heat and cause the roses to wilt.

On the other hand, if you live in a dry or cool climate, the rocks will help retain moisture and keep the soil from freezing by retaining more of the warmth absorbed during the day.