Certified GKH Gardening Expert
That is really unfortunate that they got sprayed. If there is still any green cane areas left on them, prune them down to either where there are still some good leaves or to where the green canes still look healthy. Seal the cut ends of the canes with white Elmers Glue. Wash the roses down well with water, as well as the soil. Give each of the rose bushes 1/3 cup of Epsom salts and work that into the ground around them. If you can find a product called Super Thrive at your local Wal-Mart or garden center, then get some of that. Add two tablespoons to a gallon of water. Water all the bushes you just gave the Epsom Salts with this water treatment every three days for four watering cycles. This should bring them back. Be sure to remove ALL sprayed or wilted foliage ASAP too.
If there is no green to any of the canes of the rose bushes and they are all brown, then it is too late.