Gardening with Allen: Restore lower leaf growth by pruning from middle to top

My hedge is starting to lose its leaves on the lower branches. Is there something I can do to restore full lower leaf growth?

Yes, you can gradually restore full leaf growth in the lower part of your hedge. It may take a year or two. The key is to trim the upper branches so they are shorter than the lower ones. One way to do this is to start pruning part way up the hedge. Gradually prune more and more as you go up until the hedge is narrowest at the top. Prune the lower part of the hedge just enough to achieve uniformity.

This keeps the upper branches from shading the lower ones. When lower branches are shaded, they become less productive, so the hedge plant gradually drops the leaves in the shaded area in favor of the more productive leaves receiving the most light. By keeping a hedge tapered so it is slightly narrower at the top than at the bottom, lower leaf growth stays full and leafy clear to the bottom.

Hedges are generally sheared because we want them to grow thickly and have geometrical shape. However, when we have to restore shape by making deeper cuts, it may be necessary to make individual cuts on larger branches.

If you have to prune so deeply that you go past the point where there are still leaves, you may need to compromise and do a gradual reshaping. Broad-leaf plants will normally produce new stem growth even when all leaves are removed. Needle-leaf evergreens usually will not produce new green growth if cut back to the point where there are no green leaves.

Most broad leaf shrubs like pieris, photinia, laurel, privet, spiraea, cotoneaster, pyracantha, lilac, willow, red twig dogwood and potentilla can be pruned back to a few inches above the ground to build them back to a healthy tapered shape.

Hedges do not have to be flat on top. I prefer to give them a rounded top. Of course they can be groomed into many unusual shapes if started when they are small or after severe pruning.

When other shrubs are sheared, they gradually lose their natural shape and develop thick layers of leaves. If you do not want a hedge-like appearance, prune them one branch at a time. Make some of the cuts deep inside the shrub to open space between branches.

Whenever you prune, step back periodically to look at the overall shape of the plant.

Late summer is a good time to prune hedges and other shrubs after they have made most of their growth. However, spring flowering shrubs should be pruned right away so you do not remove the flower buds that develop in the late summer and fall.

Related Stories