Roses are generally pruned according to the climate and the calendar; the ideal time to start is when growth buds swell in the spring. However, pruning rules vary somewhat with the type of rose.
Depending on your climate, pruning time for all types of roses is generally between midwinter and mid-spring. Look for forsythia to guide you: When you see its yellow flowers start to appear, you know it’s rose-pruning time. If there is no forsythia in your area, prune when new growth buds start to appear along the canes.
Modern bush roses, such as hybrid teas, floribundas, grandifloras, and miniatures, should be pruned annually when growth buds begin to swell but before they actually start to leaf out. in very warm climates where the roses may not lose their leaves, pruning should be done in mid to late winter. Since these roses bloom exclusively from new wood, pruning is essential to stimulate a good crop of new canes from which flowers can arise.
Climbers bloom on old wood — the previous year’s canes. They should therefore not be pruned until after their first flush of bloom, or wood that will produce flower buds will be cut away. However, you can cut out dead, damaged, or diseased wood at any time, and if plants need shaping, you can do this in spring, or later in the season, as you wish.
It may not be necessary to prune old garden and shrub roses every year, since the need to prune them depends on their condition, size, and shape — if these plants are generally healthy and shapely, you may not have to prune them at all except perhaps to remove dead, damaged, or diseased canes.
If old garden or shrub roses are unshapely or too large, or have been transplanted, you should perform major pruning on them after the flowers fade. Exceptions to this are hybrid perpetuals, noisettes, Chinas, repeat-blooming damasks, hybrid musks, repeat-blooming Portlands, and moss roses — all of which are pruned in early spring (if they need it) in the same way that modern bush roses are. These old garden roses are pruned early because, unlike the other old garden roses, they bloom exclusively on new wood.