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The Garden FAQ Index |

Pruning at the Wrong Time

The least desirable time to prune is immediately after
the new growth has developed in the spring. At that time,
much of the food stored in the roots and stems has been used
to develop new growth, and the new foliage should replace
this food before you prune and remove the foliage.
Otherwise, considerable dwarfing, dieback and decline of the
plant may occur.

It is also advisable to limit late summer pruning, which
stimulates new growth on some plants. This growth may not
have sufficient time to harden off before cold weather
arrives and so may be damaged or killed by low temperatures.
Late pruning also removes valuable food reserves.

Prune when twigs, branches and limbs are dry and when
the weather forecast calls for dry weather for a week. This
is most important in fall and spring, when diseases are
active and easily transmitted to vulnerable plants.
Whenever possible, avoid pruning the tender spring flush of
growth to avoid tearing new bark tissue and opening wound
sites for disease organisms to enter.

Spring flowering trees and shrubs should be pruned
shortly after flowering to avoid removing flower buds, which
form in late summer on mature wood and overwinter. Prune
plants that bloom after the end of June in late winter
before new growth starts. These plants develop their flower
buds during the spring growth period.

Bleeding of pruning wounds can be heavy on certain
trees, such as birch, dogwood, sugar maple and elm.
Minimize bleeding of susceptible trees by making small cuts
-- less than 3 inches in diameter -- and pruning in summer.
Bleeding is very likely if severe pruning is done just
before growth begins in the spring. Bleeding doesn't harm
the tree, but if it's heavy and persistent, it may injure
the bark below the pruning cut and cause slow callusing of
the lower wound.

Credit for information from the following sources: Denver Botanic Gardens, MSU Extension Office, Colorado State University Cooperative Extension