University of Maryland Extension

February Tree and Shrub Tips

winter burn on pine tree
Desication or winter burn often occurs in February. Photo: Minnesota DNR, bugwood.org

(More tips from HGIC)

  • February is the month when most ‘winter burn' (brown needles or leaves) occurs. Winter burn (desiccation) results from a combination of cold drying wind, fluctuating temperatures from very cold to warm sunny days. and frozen soil. To reduce damage, consider spraying an anti-desiccant material on vulnerable shrubs (hollies, boxwood, nandina and other broadleaf evergreens). These materials coat the foliage, preventing moisture loss. The coating does wear off, however, and will need to be re-applied one more time before the end of winter. The directions state that anti-desiccants should only be applied when temperatures are above freezing for 24 hours.
  • Trees with brittle wood, such as the Bradford pear, are very susceptible to breakage in high winds and/or by the weight of ice. Carefully, remove broken branches and make pruning cuts back to healthy wood. Avoid planting Bradford pear, silver maple, willow and other trees with weak, brittle wood because they may develop breakage problems that could damage property or hurt people. Some tree pruning work may be too dangerous for the average homeowner, refer such jobs to professionals.
  • Protect sensitive broadleaf evergreen shrubs from damaging winter winds by surrounding them with burlap or cardboard or constructing small, solid windbreaks located 18 inches from the plant on the windward side. Gently sweep snow loads off of shrubs to prevent breakage.
  • Hemlock Woolly AdelgidHemlocks infested with the woolly adelgid (photo on right) can be sprayed with dormant oil anytime between now and March 1. However, to prevent plant damage, the dormant oil directions state that it must not freeze within 24 hours of application. Finding a time that it is not freezing can be rather tricky in February. Adelgids are aphid-like sucking pests that appear as white, waxy masses on the needles. Heavy infestations can ruin or kill trees, particularly if they are stressed by drought later this summer. Infested trees can be treated with imidacloprid as a drench around the base of the tree – follow all label directions and precautions. (PDF HG 2)
  • Scale insects, like pine needle scale and hemlock scale can also be controlled with a dormant oil spray anytime that trees and shrubs are dormant. Again, be sure that temperatures are expected to remain above 40 degrees F. for a 24 hour period after spraying. 
  • The tiny reddish-brown eggs of spruce spider mites can be seen with a hand lens on the twigs and needles of spruce at this time. If you notice signs of this pest, apply a dormant oil spray, which will smother and kill the eggs. (PDF HG 13)
  • Look at the base of shrubs, especially mugo pine, nandina, azalea, boxwood and junipers, for signs of voles feeding on the bark. Voles are a type of field mouse that take cover in deep mulch and feeds on roots, crowns, and above ground wood. If you have a problem with voles remove the mulch layer and set some snap traps baited with apples or peanut butter. (PDF FS 654)
  • Do not handle the hairy poison ivy vines wrapped around trees. Be aware that the offending oil of poison ivy, urushiol, is active and can produce symptoms during any time of the year. Be very careful not to bring firewood into the house with poison ivy vines attached. 
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