Winter burn on evergreens: why needles and leaves brown in late winter, and what to do

Brown needles or leaves on the sunny, windy side of an evergreen in late winter are winter burn. The foliage lost water on bright or windy days, and roots in frozen soil could not replace it. Most burned evergreens grow out of it while their buds are alive, so cut nothing until new growth shows in spring. Young transplants, plants that went into winter dry and plants near the cold edge of their range burn worst. Bronzing or reddening is often natural winter color instead, and it usually turns green again in spring.

Bronzing and reddening are not burn

Several native evergreens change color in cold weather and stay healthy, and that winter color is the first thing to rule out before calling one burned. Northern white cedar, the wild arborvitae, turns bronze, eastern red cedar a bronzy green and creeping juniper a reddish purple. Some hollies and rhododendrons take on a yellow or purplish cast. In conifers the color follows a shift in the needles’ pigments, which guards them against winter sun they cannot use while photosynthesis is shut down.

Most of the time it is not damage, though the sources split. Maryland’s extension service lists the same colors among the signs of winter damage, with drought stress among the causes, and says they often revert as spring warms. The Chicago Botanic Garden calls the color a normal response to cold:

“The different color of the foliage in such species is not indicative of a pathogen or cultural disorder; it is a normal response to winter temperatures.” (Chicago Botanic Garden, Winter Evergreen Discoloration)

Winter color usually turns green again as spring warms. Burn is worst on the sunny, windy side, it starts at the needle tips or the leaf edges, its brown is dry and stays, and the buds beneath may be dead.

How winter burn happens

On a sunny winter day, evergreen foliage warms and starts losing water, and wind draws off more. The roots sit in frozen soil and cannot replace it, so the foliage dries and browns. In conifers the injury falls almost entirely on trees planted in the last five years.

Burn is one form of winter injury, and it shows as the snow melts. Needles brown from the tips inward, and broadleaf evergreens brown at the leaf edges first. The south, west and windward sides suffer most, while foliage under snow usually stays green. The same low sun scalds thin bark on young trunks, the subject of frost cracks and sunscald.

Salt, needle disease or winter burn

Other browning looks like burn, and each kind leaves its own sign:

• Road salt. Spray from salted roads carries up to 1,000 feet and dries conifer needles in late winter. It browns the side facing the road and can kill buds and branch tips.
• Needle disease. It works up from the lowest branches over several years, and diseased pine needles carry spots or bands.
• Old needles. Conifers shed their oldest, innermost needles in fall, white pine most of all, as the conifers that shed needles explains. Arborvitae’s branchlets brown as they age, and yew drops its needles in their third year.
• Spring leaf drop. American holly and southern magnolia shed old leaves in spring, and live oak drops last year’s leaves as its new ones open.

The native evergreens we grow, and how winter treats them

The sources name these evergreens we grow, coldest zone first:

Blue Whale Trees grows every plant in the table from seed. We do not grow boxwood, eastern hemlock or eastern white pine. Boxwood and hemlock burn the same way.

A rhododendron’s leaves roll lengthwise and droop on a cold morning, and that is not damage either. The colder the leaf, the tighter the roll, which is why rhododendrons are called nature’s thermometers. In a 2020 study, frozen rosebay leaves from Virginia unrolled completely within minutes of warming. Leaves browned at the tips and edges are burned.

What to do with a burned evergreen

Wait. Brown foliage is dead and will not green up, but the buds are hardier than the leaves and often grow out to fill the gaps. Cut nothing before new growth shows, because a conifer has few spare buds and most sit in the outer growth an early cut removes.

If no new growth has appeared by mid-spring, try the scratch test on a brown twig and peel back a bud’s scales. Green tissue under either means the branch can still leaf out, and brown means it is most likely dead.

Then cut back only what stayed brown, to a live bud or side branch. Pines, spruces and firs replace burned needles with new growth at their branch tips and seldom need cutting. Burned foliage drops from spring into midsummer as new growth comes. An evergreen burned brown all over is unlikely to recover. Where road salt reached a plant, rinse the foliage and soak the ground in early spring to flush the salt through.

Preventing winter burn

A well-watered evergreen burns less. Water through the growing season and into fall until the ground freezes, about an inch a week for an established evergreen. Soak the soil several inches deep rather than sprinkling it. Watering only in late fall does not help. Spread 2 to 4 inches of mulch out to the drip line, kept 4 inches from the stems.

Plant the evergreens that burn easily on the north or east side of a building, or in part shade. A windbreak across the prevailing winter wind shelters what grows behind it, as native hedges, screens and windbreaks sets out. Screen an exposed plant’s south, west and windward sides with burlap on stakes about 2 feet out. Leave the top open, and take the screen down in spring. Never wrap a plant tightly, since a wrap collects ice and traps moisture.

Anti-desiccant sprays divide the sources. The Morton Arboretum recommends spraying evergreens in late fall, twice in a season if needed. The extension services of Wisconsin and Minnesota disagree:

“Use of anti-transpirant products to prevent water loss from foliage over the winter has been shown to have limited benefit.” (University of Wisconsin-Madison Extension, Winter Burn)

With two of the three sources against them, water and a screen come first.

Before the ground freezes

Do the work in fall:

• Water until the ground freezes. For an evergreen shrub planted in the last two years, the watering calculator sets the dose by the pot it came in and how often to water. In winter it waters only on unfrozen ground after dry weeks.
• Send us the details if the pattern does not fit. Write through the support page and say when the browning began. Photos can follow by email once we reply.

Common questions

Will brown evergreens turn green again?

Bronze or purplish winter color usually turns green again in spring, but needles and leaves burned brown do not. The buds often survive, so wait for new growth, then cut back only what stayed brown.

Why is my eastern red cedar turning brown in winter?

Eastern red cedar often turns a bronzy or brownish green in winter, a normal response to the cold that fades in spring. Browning on the sunny, windy side that stays brown into spring is burn.

Should you wrap evergreens in burlap for winter?

Screen them instead, with burlap on stakes on the sunny and windward sides and the top left open. A tight wrap collects ice and traps moisture.

Why do rhododendron leaves curl in winter?

The leaves roll and droop in the cold, tighter the colder it gets. A curl that flattens as the leaf warms is normal and does no harm.