when to prune patio roses?

I've always done them in march and back to 2 buds with the top one outward facing, just as i would a normal bush rose. They seem to flower well. but there may be a better way.

Seaburngirl is right....March is a good time to prune. I clean out any dead wood and any crossing canes and weak canes. Try to open out the center for air circulation. I usually try to leave about 5 of the strongest canes on an established plant. Prune remaining canes back by about 1/2 unless the winter seems to have killed off more than that. Prune to an outward facing bud to keep the centre open. Seal off the cut ends if they are bigger in width than a pencil. You can use white glue, nail varnish or pruning paint. Give it a good spray with dormant oil spray if the buds haven't broken yet...if they have, then use a fungicide. Give it a bit of food and it should be beautiful.....Good luck.