How often should trees near my house be trimmed?

For established trees close to a house, a professional pruning every few years is the usual rhythm. The Virginia Department of Forestry's guideline is short: "Ideally, have a certified arborist prune trees every 3-6 years."^[1] Young trees need lighter, more frequent attention, evergreens need less, and dead or broken branches should not wait for the next scheduled visit.

A schedule by type of tree

The USDA Forest Service's Tree Owner's Manual says to prune broad-leaved trees lightly every year or every other year, starting 2 years after planting.^[2] After 10 years, frequency of pruning depends on the type of tree and amount of shade the canopy receives.^[2] Its table gives these intervals:

The manual adds a rule that matters more than the exact interval: "Pruning lightly and more frequently is better than pruning heavily and less often."^[2] For conifers, it notes that conifers usually need pruning only if they are diseased or their branches need to be raised up from the ground,^[2] and Virginia Cooperative Extension agrees that evergreen trees generally need less pruning than deciduous trees.^[4]

What happens on each visit

Some work can happen every year, whatever the schedule. The manual says broken, dead or rubbing branches, competing leaders, and branches sprouting from the base of the trunk can be removed every year.^[2]

For trees near a house, the visit is mostly about safety. The manual describes pruning for safety as removing branches that could fall and cause injury or property damage, trimming branches that block sight lines on streets and driveways, and removing branches growing into utility lines.^[2]

A good arborist also knows when to stop. The manual says no more than 25 percent of a tree's live branches should come off at any one time,^[2] and the Virginia Department of Forestry says pruning should only be undertaken when there is a clear need to meet specific objectives.^[5] Every cut is a wound, so more trimming is not better trimming.

Trees close to the roof, the wires and the driveway

The roof and siding. Limbs that rest on or rub the roof wear shingles, drop leaves into gutters and give squirrels a bridge onto the house. Ask the arborist to set a clearance from the roof and walls and keep it at each visit. Faster-growing trees beside a house may need that clearance renewed before the rest of the tree is due.

Power lines. This part is not a homeowner job, and not even a tree crew's job on its own. The Tree Owner's Manual is direct: "Never prune trees or branches that are within 10 feet of utility lines; instead contact your local utility company."^[2] Under Virginia's Overhead High Voltage Line Safety Act, no one working in a trade or business may bring people or equipment within 10 feet of an overhead high voltage line^[8][7] without arrangements with the line's owner.

Driveways and walks. Low limbs over a driveway or sidewalk are a common reason for an extra visit, especially on trees that were never trained to a clear trunk.

When in the year to prune in Virginia

The Virginia Department of Forestry says the best time of year to prune an established tree is in the winter during dormancy.^[5] Virginia Cooperative Extension adds that late winter or early spring, before bud break, is a good time to prune many species because wounds heal quicker.^[3]

The time to avoid is late in the season. Extension warns that late summer or early fall pruning causes vigorous new growth that may not harden off before winter and can be damaged or killed by cold,^[3] and advises that you avoid pruning evergreens in late summer and early fall for the same reason.^[4]

A few trees have their own timing:

• Spring-flowering trees. Extension notes that cherry, plum and crabapple form flower buds on old wood, so pruning at the wrong time can cut off the flower buds.^[3]
• Trees prone to fire blight. The manual says mountain ash, apple, crabapple, hawthorn, pear, flowering quince and pyracantha are susceptible to fire blight, and advises that you avoid pruning them from the time spring flowers emerge until the leaves drop.^[2]
• Storm damage. This does not wait for the calendar. Extension's guidance is that whenever unexpected damage from bad weather occurs, prune immediately.^[3]

Signs a tree needs attention sooner

Call before the scheduled visit if you see dead or hanging branches, a limb now resting on the roof, branches growing toward a wire, cracks in a large limb, or a branch rubbing another and wearing through the bark. Check every tree near the house after a major storm. How to tell if a tree is dead or dangerous lists the warning signs in detail.

What a good pruning job looks like

You do not need to know how to prune to judge whether it was done well.

• No topping. The Virginia Department of Forestry says topping creates large, open wounds that subject trees to decay organisms, insects and rot,^[5] and Virginia Cooperative Extension says heading or topping disfigures older trees and compromises their structural integrity.^[3] A crew that offers to "top" a tree to make it safer is offering the opposite.
• Clean cuts at the right place. The department's poster of common mistakes includes leaving stubs, which promotes branch decay, and cutting large branches flush with the trunk, which increases decay.^[6] Extension describes the right result as cuts made just outside the branch collar, leaving the collar intact to help keep decay out of the trunk.^[3]
• No paint on the cuts. Extension's guidance is that "Coatings won’t prevent decay or promote wound closure".^[3]
• Balanced, not stripped. The tree should still look like itself, with foliage spread through the crown rather than tufts at the ends of bare limbs.

When to call a licensed pro

Trimming trees near a house is pro-only on Loclis. The Tree Owner's Manual draws the line clearly: "If pruning cannot be done with both feet on the ground, hire an arborist",^[2] and "If power equipment is required, hire an arborist".^[2] Near wires, call the utility first.

Look for a company with liability and worker's compensation insurance and, ideally, an ISA Certified Arborist who prunes to the ANSI A300 standard. Do tree removal companies need a licence in Virginia? covers what to check, and what tree removal costs in Virginia explains how tree work is priced. For shrubs and hedges, see when to prune shrubs in Virginia.

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