It is now time to start preparing roses for winter.
Deadheading: Around mid or late September is a good time to stop deadheading re-blooming roses. The purpose of deadheading roses is to encourage new growth so new flowers will develop. When you stop removing spent blossoms the plant stops producing new flowering canes and many varieties of roses will set seed (hips). When roses stop producing new growth and allowed to bear hips in the fall they slip into dormancy sooner and suffer less winter damage from freezing temperatures.
Cleanup: After most of the leaves have dropped or by late November, remove any leaves that are still hanging on the canes. Also remove all leaves that have fallen to the ground around the bush. Do not put these leaves in your compost. You don’t want to spread fungal diseases that may not be killed in home composting.
It is also a good idea to cut any very tall canes down to a height of about four feet to protect them from breaking or sustaining damage during winter windstorms. This is not the time to do spring pruning. If you see a cane that is dead or severely damaged remove it from the bush at this time.
Mulching: It is a good idea to put 3 or 4 inches of compost or other mulch material around the base of rose bushes in the fall. Mulch material should extending as far out as the spread of the canes (a foot to 15 inches in diameter around the bush). This not only protects the crown and prevents the ground from compacting from rain during the winter but also provides needed nutrients to the plant for spring growth. Be sure to remove any compost or mulch that covers the rose crown by mid-March and use it to help suppress weeds around the bush.
Winter Cane Damage: For the past several years we have had relatively mild winters. But the winter of 2016 was not only very cold (temperatures dropped into the teens several times during the winter) but we also had record rainfall during the winter months. We did not add a new layer of compost or mulch to the rose bed in the Marion Garden last fall as we thought there was still enough protection from the compost we had put on the bed in the spring. When we did the spring pruning in late February we discovered there was a great deal of frost damage to many of the roses. As a result we had to remove all the dead wood from the damaged canes, often all the way down to the crown of the rose.
Fall Pruning of Climbing Roses: Late fall is a good time to prune re-blooming climbing and rambling roses after they are no longer blooming. You should stop deadheading them by mid to late September. If there are vertical canes that show signs of decline cut them off at ground level. Try not to remove more than one or two of last year’s healthy vertical canes a year. As with shrub roses begin with removing any dead, damaged, or diseased canes. Also remove any spindly, crossing, or ingrown canes. Cut back the remaining canes by about one-third their current length.
Roses that bloom only once a year in late spring or early summer should have been pruned soon after they finished blooming (usually early summer). Follow the same pruning rules as for climbing and rambling roses.