Question
Two of my dozen roses have, over many years lost some of the canes after pruning. The result is growth out of one half of the crown.  Is there a way to stimulate new growth where it is now bare?

Thanks for your good work.

Answer
Roses increase their size and height by mainly two ways. Some push up basal canes from the base of the shrub, others make only a few basal canes and then grow laterals out of the side of these main canes. As this is genetically imbedded, you can't change the way a rose bush wants to grow. However there are some roses which really resent it when you cut a cane and will make the cane die back. I have roses in my garden that when I prune them this happens so I have to cut the cane right back down to the ground level as I know it is going to die anyway. Make a note of those two roses as they will always do that when you prune them. Roses can always come back from what is known as a renewal pruning. A renewal pruning is when you cut the whole rose right back to a few inches,then  fertilized and watered well. This will make it grow a brand new bush. This should be done in the spring before new growth start. A newer rose could be cut back to 6 inches but because yours are mature and older, only go back to 12 inches if you do it.