Question: I have a number of shrubs which need pruning. Is this a good time to prune, or should I wait until spring?
Answer: Fall is one of the very best times to prune most trees and shrubs. They have gone into dormancy. Deciduous plants are losing their leaves, so it is easier to see their branch structure. The cool weather of autumn is an invigorating time to be outside.
Wait until spring or early summer to prune flowering shrubs such as lilac, spiraea, and forsythia. These plants have already developed their flower buds for next spring. You might as well enjoy the flowers first before pruning. I have also found that roses and most fruit trees winter over with less damage without pruning. They are best pruned in March or April.
Begin with the end in mind is a good plan to follow when pruning. However, the end to look for is not just when the pruning job is finished, but what the plant will look like after growth has taken place next year.
Reducing size is often one of the main goals when pruning shrubs. However, pruning every branch of a shrub which grows beyond the desired outline of a reduced size will stimulate an explosion of growth next spring. Several times as many branches will grow, producing a plant which is much thicker.
A much better pruning method is to prune one branch at a time, with the longest branches cut back inside surrounding growth so that stubs are hidden. If branch growth is too thick, remove some of the most vigorous branches clear back to where they began growing. Most branches should be cut back to a side branch. If no side branches are growing on a particular branch, prune just beyond a bud or remove the branch entirely. Don’t prune every branch to the same length. The natural shape of shrubs is not perfectly round or flat on the sides or top.
Evergreen shrubs such as junipers have quit growing on the inside where adequate light is no longer available. If plants are cut back enough that there are no longer any green needles, they will not regrow green growth. Rather than creating ugly brown areas, it is better to remove the plant and replace it with a new, smaller plant which will not outgrow the desired size.
In addition to removing dead branches in deciduous trees, other branches which are rubbing and crossing each other can be thinned. In most cases branches should be cut back to their origin, rather than just shortening. In choosing which branches to remove, leave the ones growing outward, and remove those which grow inward or straight up.
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