Q.
I have a neighbor concerned about his rosemary and boxwood hedges. He has been
having trouble with the foliage browning and falling off. His landscapers
recommend he cut them to the ground but he opted to cut them back by half
instead and let them regrow. Can you tell me a little about these and your
opinion about how to properly care for and what he should do to get them
looking their best again?
I have a neighbor concerned about his rosemary and boxwood hedges. He has been
having trouble with the foliage browning and falling off. His landscapers
recommend he cut them to the ground but he opted to cut them back by half
instead and let them regrow. Can you tell me a little about these and your
opinion about how to properly care for and what he should do to get them
looking their best again?
 |
| boxwood |
A.
When rosemary and boxwood, or any plants for that matter, are continuously
pruned with a hedge shears it causes them to get thick and bushy at the point
where they are continuously sheared. This increases their density on the outer
edges of the plants.
When rosemary and boxwood, or any plants for that matter, are continuously
pruned with a hedge shears it causes them to get thick and bushy at the point
where they are continuously sheared. This increases their density on the outer
edges of the plants.
Shearing causes the interior of the
hedge to become very dark. This darkness cannot support leaf or new stem
growth. The older stems on the inside of the hedge drop their leaves.
hedge to become very dark. This darkness cannot support leaf or new stem
growth. The older stems on the inside of the hedge drop their leaves.
All the new growth occurs only where
it is sheared. Perhaps only an inch or two of the outer surface of hedged
plants have leaves. The dark interior is leafless.
it is sheared. Perhaps only an inch or two of the outer surface of hedged
plants have leaves. The dark interior is leafless.
If we cut too far back into the
hedge 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 usually occur on the older wood.
hedge 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 usually occur on the older wood.
The rate of recovery of this older
wood depends on the plant. Rosemary will come back faster than boxwood.
wood depends on the plant. Rosemary will come back faster than boxwood.
 |
| rosemary |
He will start to see growth coming
from older wood exposed to sunlight as suckers. In technical terms we call this
adventitious growth. Boxwood will do the same thing but it is much slower to
react and fill in.
If he is patient he will see new
growth slowly fill in the canopy.
growth slowly fill in the canopy.
If he had cut it back close to the
soil surface, the same thing will occur on the Rosemary but it will be slow to
grow back into a hedge. Boxwood will even be slower.
soil surface, the same thing will occur on the Rosemary but it will be slow to
grow back into a hedge. Boxwood will even be slower.
In cases like these most people do
not want to look at a hedge trying to fill back in and would elect to replace
these plants.
not want to look at a hedge trying to fill back in and would elect to replace
these plants.
Once plants are cut with hedge
shears for a couple of seasons they are very difficult to reestablish again as
plants that are no longer a hedge. The interior of the hedge is just too woody.
shears for a couple of seasons they are very difficult to reestablish again as
plants that are no longer a hedge. The interior of the hedge is just too woody.