Prune and fertilize roses now through early September to encourage a colorful bloom this October and November. A light pruning will get rose bushes in shape for the fall blooming season, particularly the everblooming hybrid teas and grandifloras. Fall blooms normally will peak 45-50 days after pruning, although this somewhat depends on growing conditions.
The tools you will need include a sharp bypass hand pruner and a pair of leather gloves. You will also need bypass loppers if you have to cut woody canes larger than one-half inch in diameter.
The following recommendations are primarily for hybrid tea and grandiflora roses. Examine your rose bushes for dead canes and weak growth. Remove all dead growth. Make your cuts well into the healthy part of the canes just above a leaf or dormant bud or remove the dead cane entirely back to its point of origin.
Next, remove weak, spindly canes the diameter of a pencil or less, particularly those growing in the interior of the plant. Cut them off at their point of origin, making sure you don’t leave a stub. The major part of the pruning involves shortening the remaining vigorous canes. This will produce a fuller, more attractive bush with larger, better-quality flowers this fall.
On vigorous plants, cut the canes back to about 30 inches from the ground. Ideally, try to make each cut just above a bud that faces outward, away from the inside of the bush. The cuts should be made about one-quarter inch above the bud at a slight angle slanting away from the bud.
Clean up and dispose of all leaves and prunings from the area and fertilize the roses to encourage vigorous new growth. Use your favorite rose fertilizer according to label directions or use a general purpose fertilizer.
Everblooming, old garden roses, shrub roses, landscape roses and other groups also may be pruned now, but the pruning required is generally less severe and is done mostly to shape the bush or to control the size of more-vigorous varieties. Use your best judgment when it comes to pruning these roses. As a general rule of thumb, these roses are cut back about one-third their height in late summer.
With old garden roses you can look at the situation and how the rose is growing, and then prune accordingly based on how you want the rose to look. Some gardeners prune their bushier roses with hedge trimmers. This is a particularly effective technique if you have planted a long hedge of roses that would take a long time to prune with hand pruners. On the other hand, this clipped appearance may not be suitable for roses growing in garden beds.
Some roses – including many climbing roses, ramblers and old roses – only bloom once in spring and early summer. Unlike everblooming roses, they should not be pruned back extensively now because they will produce next year’s flowers on the growth they made this summer. Cutting them back now, or any time before they bloom next year, will reduce the number of flowers they produce. So, keep pruning to a minimum – if you prune at all.