General advice about roses.
Water roses at the same time and in the same amount as your lawn.
The best time for pruning roses is in early spring, before the roses start leafing out. However, I have always pruned whenever I could, as long as the weather was comfortable to be outside and no frost was forecast. I used to have about 20 rosebushes, so I would never really be done with the pruning.
The only obvious pests I have encountered on my roses are aphids. You can kill them with soapy water, but most of the time it is just easier to prune off the part that they are on. I have never had them totally infest the entire bush. If your roses are healthy they will always be growing new stems and flowers. If you have a problem on any part of an otherwise healthy rosebush it is usually just easier and better to prune the bad part off. More will grow.