Moving the rosebush outside after the overwinter period puts the rosebush into a bit of shock, kind of like transplanting it will do. It has to get used to the outdoor environment again and the temperature ranges. Once it get settled in and comfortable, you should see some new growth. To help with the shock and stress the rosebush is dealing with, add some of a product called Super Thrive to the water in the watering can you water with. Follow the directions on the product label. I typically also add some root stimulator to the same water so the rosebush gets both. It really does help them deal with any stresses and shocks to get to growing again. If the night time temps where you are dip into the high 30's, that will slow the growth down on the rosebush. They need consistent 40 degree nights at least to really get their growth going well.
Stan The Rose Man
Gardening Know How