Do Camellia Bushes Lose Their Leaves in Cold?

Cold, Wet Roots

• According to Klaus Peper of the International Camellia Society, if roots of potted camellia plants get too cold or wet in late winter or early spring during an unexpected cold snap, then several weeks later leaves may suddenly drop. Camellias are much more vulnerable to cold when grown in containers. Drastic action, Peper says, can often save the plant. When cold-related leaf drop occurs, both new leaf buds and flower buds usually remain. But because roots have been damaged, the plant can’t support new growth. Peper suggests pruning plants severely, removing all flower buds. Keep recovering camellias in a protected but cold greenhouse and atop a 20-watt aquarium heater plate to provide mild soil warmth.

Winter Leaf Burn

• Sudden subfreezing weather can devastate camellias, says William L. Ackerman, who is well known in camellia circles for developing cold hardy U.S. National Arboretum cultivars. Early morning winter sun can damage or kill camellias by causing leaf burn -- a form of freeze-drying. Sun shining on dark, green foliage creates a leaf surface microclimate, which is warmer by 10 to 15 degrees Fahrenheit than surrounding freezing air. In low relative humidity -- common during severe cold -- this warmth draws moisture from the leaves. But because the soil and its water are frozen, camellias can’t replace lost moisture. Leaves quickly die, turning pale, greenish-white and becoming “as brittle as corn flakes,” in Ackerman’s words. Provide winter shade protection for vulnerable camellias so they remain fully dormant, even when the sun comes out.

Cold-Climate Culture

• Camellia growers in colder climates need to plant and care for camellias differently -- starting with selecting plants based on hardiness. Make thoughtful, strategic use of protective buildings, fences, hedges and other windbreaks when locating your camellias. Contrary to popular opinion, Ackerman says, with protection from prevailing winds, a northern or northwestern exposure is best for camellias in northern regions. The goal is to encourage camellias to go dormant in early autumn and stay dormant. From Maryland north, he suggests planting camellias in the spring rather than fall, so new plants are well established -- with strong, vigorous roots -- before the stress of their first freezing winter.

Other Cold Precautions

• The American Camellia Society recommends low levels of nitrogen relative to potassium and phosphorus in fertilizers applied late in the season to decrease winter injury by increasing soluble salts in plant sap. Loamy but well-drained soils with optimal moisture retention and aeration also help camellias withstand stress. Water plants less frequently but deeply to encourage deep root development, which also will aid in stress tolerance. Protect camellias with microfoam or burlap cold shields during their first winter.