University of Maryland Extension

January Tree and Shrub Tips

gypsy moth and egg case
Photo: To reduce gypsy moth numbers look for and remove their tan colored egg masses.

(More tips from HGIC)

  • You can reduce gypsy moth numbers by removing and destroying the tan colored, felt-like, 1 ½ inch long egg masses (see photo above). They can be found on tree bark, firewood, lawn furniture and other outdoor structures and scraped off wherever found. Read:
  • bagworms on pineRemove and destroy bagworm bags from affected trees- principally on evergreens. (Photo on right) The bags contain hundreds of eggs that will hatch out and feed next spring. (PDF HG 32 Bagworms)
  • Scale insects, like pine needle and hemlock scale, can be controlled anytime that trees are dormant with a dormant oil spray. Spray trees and shrubs that have had aphid (PDF HG 83 Aphids on Ornamentals), mite (PDF HG 13), or scale problems with dormant oil. Be sure that temperatures are expected to remain above freezing for a 24 hour period after spraying.
  • Eastern tent caterpillar egg massEastern tent caterpillar egg masses resemble black Styrofoam and are most often located on the ends of wild cherry trees; they will also feed on plum and crabapple trees (Photo on right). Clip them off with pole pruners and throw them in the trash. The fuzzy, tan-colored, capsule-shaped pupal cases you find on wooden structures contain Eastern tent caterpillar pupae. (PDF HG 21 Eastern and Forest Tent Caterpillar)
  • Trees and shrubs can be pruned now. Remove dead, diseased branches and make any necessary cosmetic cuts. Remove broken branches and make pruning cuts back to healthy wood. (PDF HG 84 Pruning Ornamental Plants)
  • Try to prevent snow and ice from building up on gutters and eaves above shrubs. Gently sweep snow loads off of shrubs to prevent breakage.
  • Refrain from any hard pruning of vines like clematis until early spring when winter damage can be fully assessed. Consult local nurseries and garden catalogs for appropriate varieties for spring planting. It is best not to plant clinging-type vines on or near wooden structures.
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