Step 1: Retain Old Wood
Retain old wood, except for any diseased, dead, or weak growth, which should be cut down to the ground or to a healthy bud.
Step 2: Reduce Sideshoots
Only prune the sideshoots, reducing them to about two-thirds of their original length, and cutting to a bud facing in the right direction.
Step 3: Provide Stem Support
Tie in the newly-pruned stems horizontally to their support. This encourages more flowering sideshoots to form along the stems.
Step 4: Trim Longer Stems
Prune back any too-long stems that are protruding beyond the support, and sideshoots growing away from it.
Bush roses include hybrid teas and floribundas, both of which need to be pruned hard each year to encourage new growth.