Friday, June 18, 2021
June 18, 2021

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Gardening With Allen: Shrubs can regain their natural shape with careful pruning

Allen Wilson on pruning


I recently bought a house that has shrubs sheared flat next to the sidewalk and lawn. They have also been pruned flat on top. I love my house but hate these ugly shrubs. Is there anyway I can prune to return them to more of a natural shape? Can I prune now or should I wait until spring? Or should I just pull them out and plant new ones? I have both evergreens and broadleaf shrubs which lose their leaves.

Yes, shrubs that have been sheared so they have lost their natural shape and thickness can be recovered. Plants are entering dormancy right now so the next couple of months would be a good time to prune. Or you could wait until March or April to prune. If you prune the flowering shrubs before they bloom next spring, you will remove the flowers. Depending on their condition, you may want to sacrifice the flowers and prune anyway.

The main pruning cut needed to return sheared shrubs to a natural shape is thinning. This means removing about a third of the branches deep inside the shrub. Plants that have been sheared several times will have clusters of three or more branches growing out from the same point. Deeper in the plant, you will probably find another cluster. Prune below the first and second clusters if possible. With one cut, you will be removing three to 12 branches or branchlets. Prune the remaining branches to a natural round or curved shape leaving the lower branches the longest. I like to start at the bottom of the shrub and gradually prune branches shorter as I move up.

Some deciduous shrubs that have become overgrown can be drastically pruned back to within a few inches of the ground. They will quickly grow new branches and can be pruned to retain a natural shape as they grow larger. Rhododendron, azalea, nandina, escallonia, potentilla, red twig dogwood, blue arctic willow, spiraea and lilac will all respond to this type of pruning. Remember, however, that you are sacrificing a year’s flowering when you do this. Potentilla will bloom the same summer after being cut back in the fall or spring.

Evergreen shrubs with needle shape leaves will not produce new green growth if pruned back to where there are no green needles.

Where branches are growing out over the lawn consider moving the lawn back so you have a wider bed for the shrubs. This will leave more room for shrub growth without drastic pruning. Where shrubs are growing over a walkway or blocking windows, your best choice may be to remove them.

Carefully check labels so you replace the shrubs with ones that will not grow beyond the size you want them. Replace shrubs that lose their leaves with broad leaf evergreens like dwarf nandina, dwarf escallonia and dwarf pieris.