When you have roses, you have to water them about one inch of water per soil. It can depend on the soil how often you need to water. Sandy soil need frequent watering, but as a rule of thumb once a week is good for most soils.
Using mulch on the soil around the plants to retain the moisture in the soil is a good practice. Mulch will also keep down the growth of weeds and keep the soil cool. Use mulches of dry grass clipping, wood chips or straw. Mulch needs to be applied about 2-3 inches deep. Remember to replace it when it needs to be replaced. Even though using mulch is good. Organic mulch can bind up the nitrogen as they decompose, so you will need to fertilizer to prevent deficiencies in the soil.
For roses to stay healthy and strong you will need to make yourself a fertilizer schedule. This will need to be performed yearly and the schedule will vary depending on the type of roses you are growing. Check with a plant expert in your town to find out, what type of fertilizer schedule you will need for your roses. As a rule of thumb general-purpose fertilizers like the 10-10-10 or the 12-12-12 are usually adequate. The ration is