The first day of summer is rapidly approaching, along with the usual extremely high temperatures and hot nights. If you transplanted now, you would have to constantly monitor the plants very closely and keep them well hydrated. A better time might be around the first week in September, with it's cool nights. What you can do in the meantime is get a shovel and thrust it straight down into the ground in a circle around each rose, about ten inches away from the trunk. This will sever any wandering roots and force the rootball to become more compact. You can repeat this in July and then again in August. When you do finally go to transplant the bushes, the roots will be ready and the plant will suffer less trauma. You might also look for a product like Shultz's B1 transplanting formula or seaweed (kelp) extract which will help the plant make the adjustment.