How to Prune Evergreen Shrubs and Hedges

Two kinds of evergreen

Narrow-leaved evergreens — junipers, yews, arborvitae, and the pines, spruces and firs — are pruned before new growth begins. Iowa State prunes junipers and yews in late March or early April, and says light pruning can also be done in midsummer. Illinois prunes them in March or April. Missouri does any severe pruning of junipers and yews in April, and of arborvitae in March or April, and says light pruning may be done at any time of year.

Broadleaf evergreens mostly need little pruning. Missouri says most grow slowly; Iowa State prunes rhododendrons immediately after flowering. Missouri prunes both azaleas and rhododendrons after flowering, and snaps off rhododendron flower stems as soon as flowering ends, leaving the small buds at their base, because waiting can cut the next year’s flowers.

Not in fall, for either kind. Iowa State says fall-pruned evergreens are more susceptible to winter injury, and Illinois says any new growth after a fall cut is susceptible to winter injury.

Junipers, yews and arborvitae

• Cut back to a side branch. Missouri says more compact plants result when long branches are pruned back to where they join a side branch in early spring, cutting “back in” so new growth soon covers the stub.
• Junipers: keep green on every branch. Missouri says green foliage must remain on any juniper branch that is cut back; junipers seldom grow new shoots from bare stubs.
• Yews: more forgiving. Missouri says yews can be cut back more severely and often survive a 50 percent size reduction, and that a vigorous yew may need a second light pruning later in summer for the long shoots.
• Arborvitae: mind the dead zone. Arborvitae and juniper develop a dead zone in the center of the plant, and Missouri says cuts must not reach it. It says an overgrown arborvitae cannot be cut back more than 20 percent, and a pyramidal juniper can lose about 20 percent of its height but no more.
• Too big is a siting problem. Clemson says boxwoods, junipers, pines, cypress, cedar, arborvitae, yews and other narrow-leaf evergreens do not respond to severe pruning and may decline, and that transplanting may be better than pruning when they outgrow a site.

Boxwood, holly and other broadleaf evergreens

• Boxwood. Iowa State says boxwoods often die back in severe winters: prune out the dead growth in early to mid-April, shape lightly from spring to midsummer, and do not prune in late summer, when the late growth may not harden before winter.
• Azaleas and rhododendrons. Missouri prunes them after flowering, never cuts into areas of bare stems or sparse foliage, where they sprout poorly or not at all, and takes no more than a third of the branches in a season when a hard pruning is needed — so the job takes three years.
• Gardenias. Clemson’s list puts gardenias with the shrubs pruned before spring growth; the gardenia page gives the after-flowering timing from Clemson’s own gardenia page and UF/IFAS.
• Holly. Missouri says American holly stands heavy pruning and is often pruned at Christmas, when the branches can be used indoors; Japanese hollies seldom need much.
• Mahonia. Missouri removes old shoots with bare stems at ground level, and the stumps sprout new growth.
• Broadleaf shrubs that can be cut hard. Clemson says azaleas, camellias, privets, glossy abelia, nandina and cleyera respond well to renewal pruning — cutting to within 6 to 12 inches of the ground before spring growth begins.

Pines, spruces and firs

Iowa State says evergreen trees such as pine, spruce and fir need little pruning, and that dead, broken and diseased branches can be removed at any time of year. Spruces and firs carry side buds on their newest growth, so to thicken them Iowa State and Illinois cut shoots back to just above a side bud or branch in early spring; Minnesota says late winter, before growth begins, is probably best. Pines grow only from the buds at the branch tips, so Iowa State pinches off half to two-thirds of each new “candle” in spring when it is 2 to 3 inches long, and never cuts back to bare stem, which will not regrow. Missouri removes about half of each candle on mugho pines once it has nearly finished lengthening.

Missouri says spruces recover from cuts back to 2-year-old wood and firs to 3- or 4-year-old wood, but that if they are sited well none should need much pruning.

⚠️ Lower branches: the sources disagree. Iowa State says late winter is the best time to remove unwanted lower branches on evergreen trees. Illinois says removing lower branches is not advisable, because it compromises the tree’s structure.

Hedges: wider at the bottom

The shape. Iowa State, Missouri, Clemson and UF/IFAS all trim a formal hedge so the base is wider than the top. Iowa State says the pyramid lets the lower branches get the sunlight they need to stay full, and sheds snow that would break branches; UF/IFAS says the most common mistake is a sharp-edged box, whose bottom branches thin out and can die for lack of light.

The timing. Iowa State does extensive pruning of most deciduous hedges late in the dormant season, late February and March in Iowa, and begins evergreen hedges in April; it shears evergreen hedges in late spring or early summer, May to early June, just after the new flush, and avoids heavy pruning after midsummer. Clemson and UF/IFAS clip formal hedges while the new growth is green. A flowering hedge is sheared after it blooms (Clemson, UF/IFAS), and Iowa State says pruning a lilac hedge in the dormant season removes many of its flowers.

How often. Iowa State says most hedges need 2 to 4 trims a season, and the tidiest almost monthly; Missouri says at least twice a year. Iowa State does not recommend formal hedges for most home gardeners because of the time they take, and says most deciduous shrubs should not be sheared into formal hedges at all; privet, alpine currant and barberry are the exceptions.

Starting one. Missouri says a dense hedge must be grown slowly, never pushed to its height in one season, and that privet and barberry need severe pruning right after planting and at the start of the second year to make them bushy. Clemson cuts young hedge plants to within 12 inches of the ground and tips new shoots during the season to make them branch. An informal hedge, left in its natural shape and trimmed only as needed, is Clemson’s choice for a low-maintenance garden.

Renovating one. UF/IFAS cuts overgrown shrubs to within a few inches of the soil in early spring, or, because that does not work for all shrubs and especially not certain evergreens, takes out a third each year for three years.

Common mistakes

• Cutting a juniper back to bare wood. It seldom regrows (Missouri).
• Cutting into an arborvitae’s dead zone. Missouri’s limit is about 20 percent.
• A hedge wider at the top. The bottom goes bare (Iowa State, UF/IFAS).
• Pruning evergreens in fall. More winter injury (Iowa State, Illinois).
• Shearing boxwood in late summer. The new growth may not harden (Iowa State).
• Shearing shrubs that are not hedges. Missouri says once sheared, a plant’s natural form is almost impossible to restore.

Every pruning guide

• When to Prune by Zone: Late Winter or After Flowering
• When and How to Prune Roses by Zone
• Pruning Fruit Trees in Late Winter: Apple, Pear, Peach
• How to Prune Flowering Shrubs: Spring vs Summer Bloomers
• What Not to Prune in Fall, and the Cuts That Are Fine
• How to Prune Evergreen Shrubs and Hedges — this page
• How to Prune Hydrangeas by Type: Old Wood vs New Wood
• Hydrangea Pruning Chart: When to Prune Each Type
• How to Prune Limelight Hydrangea and Vanilla Strawberry
• How to Prune Annabelle and Incrediball Hydrangeas
• How to Prune Endless Summer Hydrangeas (Rebloomers)
• How to Prune Oakleaf Hydrangea: After It Flowers
• Hydrangea Tree Care and Pruning (Tree-Form Panicle)
• How to Prune Crape Myrtles Without Crape Murder
• Your USDA hardiness zone by ZIP code

Where there is no source here

We found no Texas or Georgia source on pruning evergreens and hedges we could read; University of Georgia Extension’s pages would not load from here. The South is covered by Clemson for South Carolina and UF/IFAS for Florida. For protecting evergreens from winter burn, wind and snow, see how to protect shrubs in winter.