Boxwood Hedge Slower to Recover From Pruning Damage Than Rosemary

Q. I have a neighbor concerned about his rosemary and boxwood hedges. The foliage has been falling off. Landscapers recommend he cut them to the ground to get them to recover but he opted to cut them back halfway instead. Now there is a lot of bare wood exposed with no leaves. What should he do to help them recover?
A. When plants are continuously pruned with a hedge shears it causes them to get thick and bushy.

            This increases their leaf density on the outer edges of the hedge. This causes the interior of the hedge to become very dark and the stems on the inside of the hedge to drop their leaves.

            They also drop their leaves because the wood on the inside is old. All the new growth occurs where the hedge is being cut over and over. So perhaps only an inch or two along the outer surface of the hedge has leaves.

            If we cut the hedge back more than a couple of inches, we expose the older wood that has no leaves. The wood is alive, but without leaves. Once this interior wood begins to receive sunlight again, new growth will sprout from this older wood.

            The rate of growth from this older wood depends on the plant. Rosemary grows faster than boxwood. If he is patient, he will eventually start to see new growth coming from the older wood. Boxwood will also have new growth but will fill in slower than rosemary.

            If he is patient both hedges will eventually slowly fill back in but boxwood will be much slower. In cases like these most people do not want to look at an ugly the hedge for the next few years and would elect to replace the damaged plants.

            Once plants are cut with hedge shears for a few years over and over they are very difficult to reestablish again as plants that are not shaped like a hedge.