Coffee grounds can be a good, free and nutrient dense soil enhancer for rose bushes. There are some concerns about coffee grounds affecting soil pH. As coffee grounds decompose the pH in them neutralizes, meaning the soil's pH isn't affected drastically by it.
There are a number of ways to make coffee grounds even more useful for rose bushes. Placing the grounds directly in a hole near the roses stimulates growth as the acid content of the coffee grounds are enjoyed by roses. Coffee grounds can be added to compost as a green composting material. Spreading a thin layer of coffee grounds on the soil creates a good slug barrier and helps provide a nutrient rich environment for earthworms.