Shrubs and trees can be pruned to improve structure, maximize blooms and/or fruit production, or to remove damaged or diseased branches. Such branches should be removed as soon as possible. They provide portals for pathogens to infect or infest the tree. Do not use a wound sealer, as this causes more harm than good.

Pruning should not be used to control size; instead employ better plant selection to properly size woody plants.

When to prune woody plants has a simple answer: It depends! The first key to the actual answer, is to identify the plant. Pruning will stimulate plants to produce new growth. Most of the timing is based on a need to protect tender new growth from late and early frosts.

If you know exactly what your tree or shrub is, a bit of research will give you the information you need to prune at the optimal time of year. Specific identification can be difficult. Observing the shrub can give you big clues about when to prune. The answers to these three questions will guide the timing.

• Does it bloom before or after June 15?

• Is it evergreen or deciduous?

• If it is evergreen, does it have needles or broad leaves?

Deciduous shrubs: Shrubs that bloom early set buds on wood grown in prior years. Pruning early will remove all or some of this year’s bloom; prune after the bloom. Later blooming shrubs flower on this year’s growth. Pruning in early spring will maximize the bloom this year.

What about shrubs that don’t bloom? These are generally shrubs that are described as having an inconspicuous bloom, since you probably don’t notice the bloom; go ahead and prune early.

Deciduous trees: Best pruned in late winter during dormancy. Bare branches make it very easy to see the shape of the tree and determine which branches are best removed.

Broadleaf evergreens: Boxwood, mahonia and holly are examples. New growth is quite susceptible to frost damage. Wait until mid-May to prune these shrubs. Avoid pruning these shrubs after mid-July to avoid early autumn frost damage.

Conifers: Conifer trees generally require little pruning as their natural morphology generally is quite pleasing. Small varieties like Mugo pines can benefit from cutting the new growth (candles) back to encourage a bushier shrub in spring. Low-growing spruce trees like Picea globosa can be trimmed in late winter to smooth out its mounded shape. Pine branches produce new needles only at the tips. If you must remove a pine branch, cut it all the way back to the trunk.

August through October is a no-prune period. Other than weather damage or disease, pruning then generally is not beneficial for woody plants.

For more information on pruning, check out the science of pruning

Submit gardening questions to csumg2@elpasoco.com or call 719-520-7684. The in-person help desk is open 9 a.m.-noon and 1-4 p.m. Mondays and Wednesdays at 17 N. Spruce St. Find us on Facebook at Colorado Master Gardeners – El Paso County.