Answer: Roses do best in a spot with full sun all day long and good air circulation. They need average or better soil that is evenly moist yet well drained, meaning not sopping wet or saturated.
Most roses will do fine with an annual top dressing of a good quality compost in early spring plus an application or two of general purpose granular or slow release fertilizer with an analysis of 10-10-10 on the label. Read and follow the label directions. With a new rose I would not worry about fertilizing until next spring but you could apply compost to the soil surface under your mulch.
Mulch with an organic mulch in a flat layer several inches thick over the entire root area. Do not allow it to touch the stems. Depending on what kind of rose you have, you may need to mulch very heavily in late fall, or you may need to hill soil around the base of your rose to protect the graft.
The most important thing you can do is make sure the soil stays slightly damp all this season while it it becoming established. Your goal is to supplement rain -- so you may or may not have to water much, depending on the weather. To know if you need to water, dig into the soil with your finger. If it is still damp, don't water yet. When you water, water slowly at the roots and let it sink in deep to encourage deep rooting. You can water any time of day although early morning is probably best. Avoid wetting the foliage no matter what time you are watering. After watering, wait a few hours and then dig down to see how far the water soaked in; it can be surprising. It is better to water less often but deeply than to sprinkle lightly every day.
Good luck with your rose!
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