Cold Tolerance for Red-tip Photinia Bushes

Characteristics

• Red-tip is an evergreen shrub that usually becomes 10 to 15 feet tall with an equal spread at maturity. Its color is brightest in spring and early summer, when the season's growth is still young. Its leaves are leathery and become glossy and dark green as they age in mid- to late summer, but mid-season pruning can stimulate colorful new growth. The plant has small white flowers in April that are borne in flat clusters, or panicles. The inconspicuous flowers have an odd, slightly unpleasant aroma and are easily eliminated by spring pruning before buds open.

Climate

• In the colder parts of red-tip's range, USDA zone 7, winter temperatures frequently fall below freezing and can reach 0 degrees Fahrenheit for short periods of time. Red-tip can withstand these temperatures and usually produces healthy new growth in spring, but an extremely cold winter might cause some loss of foliage or drying of its leaves, especially when strong winter winds occur regularly. Although the plant withstands summer heat well, it needs some chilling during winter, which it experiences in the warmer part of its range, USDA zone 9, where sub-freezing temperatures often occur for short periods. Red-tip isn't a good choice for regions above zone 9, because it's unable to enter winter dormancy in these areas, where winters are relatively warm.

Site Selection

• If you live in USDA zone 6, where red-tip may grow if protected in winter, or if your area is within its normal range but tends to have especially cold winters, choosing a good site for the plant can help it come through winter well. An ideal location is near a warm, south- or west-facing wall of a building, or you could plant red-tip on a hillside, where cold air drains away to lower portions of the slope. A spot that's protected from winter wind, such as near larger trees or along a solid fence or wall, can also help red-tip survive cold weather undamaged.

Protection

• Adding a thick, 4- to 6-inch thick layer of mulch around the root zone of photinia in fall and renewing it if disturbed by wind can help keep the plant's roots warm during winter, while also protecting it from heaving of ground during freeze-thaw cycles. Watering the plant well in late summer through fall also builds up the plant's resources and helps prevent stress, also preparing it for cold weather. If you prune a red-tip shrub, avoid doing so in fall, since this stimulates new growth that's especially susceptible to damage from cold.