Each spring, many homeowners in Georgia discover dead, brown foliage on their evergreen plants.
Often mistaken for diseases, most of these dead spots are the result of cold damage. Even after a seemingly mild winter, evergreen plants in Georgia can still be susceptible to winter desiccation injury, also known as "winter burn."
Although we don't see as much winter injury as some colder parts of the country, we do experience a fair amount of cold damage, especially on newly-transplanted plants and young, succulent tissues.
Both broad- and narrow-leafed evergreens are often subject to winter burn, including junipers, pines, Leyland cypress, azaleas, arborvitae, hollies, rhododendrons, boxwoods, nandinas and photinias.
Winter burn can occur when the plant experiences low soil moisture, freezing temperatures and strong winds.
Because they retain their foliage throughout the winter, evergreens are continually transpiring water through their leaves or needles.
If low soil moisture or sub-freezing temperatures combine with heavy winds, the plant's roots cannot adequately replace the water that is lost during this period of rapid transpiration.
When water usage exceeds available water, the needles, leaves and twigs dry out and die.
This rapid transpiration directly causes the winter burn symptoms, according to UGA Plant Pathologist Dr. Jean Williams-Woodward.
Foliage often appears brown or bleached, which can often be mistaken for insect of disease damage. Often seen on evergreens like azaleas, new blooms will appear brown and shriveled.
If all the blooms on a plant are dead, then the damage is likely due to environmental causes rather than plant disease organisms.
Of course, winter injury is not limited to evergreen plants. Deciduous plants can also fall victim to cold temperatures.
Dead leaves, dead branch tips and necrotic blooms can occur from an early spring freeze event.
Regardless of the type of winter injury seen, it is often beneficial to wait until mid-spring to assess the damage.
Often, blooms and buds will sprout from areas that at first appeared to be completely lost. Some evergreens, like hollies, may eventually produce enough new leaves to fill in the voids.
Prune out dead twigs and branches about an inch from live tissue, or back to the collar of the next live branch.
Removing the dead and damaged leaves and blooms will help stimulate new plant growth. Pruning also helps to reduce the chance of secondary plant disease organisms infecting the dead branches.
Once the weather warms up, it is important to fertilize the injured plants early.
This will help to stimulate new growth.
Irrigating the injured plants throughout the season will also help prevent future winter burn.
Occasional deep watering, even during the winter months, will help ensure adequate water is available for your plants year-round.
A 3 inch layer of mulch is also recommended to help retain appropriate soil moisture.
Clark MacAllister is the Dawson County extension agent. For more information, call (706)265-2442