Monthly Tips for December


  • To keep holiday plants looking good longer, keep them away from dry, drafty locations. Do not place near heat vents, doorways or drafty windows. Increase humidity around plants by placing them on a tray lined with pebbles, shallowly filled with water. Make sure the water does not enter the drainage holes. 
  • Winter is a challenging time for most houseplants because of the lower natural light and susceptibility to being over-watered.  Growing media should be allowed to dry out between watering.
  • Unless your indoor plants are growing under optimum, high light conditions, do not fertilize them during the winter months.


Mantid Egg Case
Mantid Egg Case
  • You may notice insects and spiders emerging from around your Christmas tree. They came in unnoticed on your tree. Simply escort them outside or vacuum them up.
  • The brown marmorated stink bug is settling down in nooks and crevices in houses and buildings for the winter. You may see several moving about in your home especially on warmer sunny winter days. Do not use insecticide sprays in your house to kill them. Capture and dispose of them using your shop vac. The stink bug is likely here to stay for a while, but like all insects may display fluctuating population cycles.
  • Miscellaneous beetles, like long-horned beetles and bark beetles may emerge from firewood stored inside the home. These are nuisance pests; they are not a threat to the wood in your home. You can also prevent pests from coming into the house by storing firewood outside the house.

Trees and Shrubs

  • In a “normal” year in our region we do not get much ice or snow in December, but if we do, try to prevent it from building up on gutters and eaves above shrubs. Heavy snow and ice loads can break branches. Using an upward motion, gently sweep snow loads off of shrubs to prevent breakage. Sweep snow and ice off shrubs with an upward motion.
  • Trees and shrubs can be pruned now. Remove dead or diseased branches and make any necessary cosmetic cuts. Remove broken branches and make pruning cuts back to healthy wood. Extensive pruning of spring flowering plants such as azaleas, rhododendrons, and dogwoods will reduce the number of blooms in the spring. If you do not desire to reduce flowering, wait until after they bloom next spring to prune them. (Watch our pruning videos)
  • Evergreens such as hollies, boxwoods, and pines can also be moderately pruned this month. The trimmings can be used for holiday decorating.

More tips from the Home & Garden Information Center

The Home & Garden Information Center’s horticulturists are available year-round to answer your plant and pest questions. In addition to gardening questions, we cover houseplants, indoor pests, and more. Send your questions and photos to Ask an Expert!

One thought on “Monthly Tips for December

  1. George Lambert December 6, 2018 / 9:59 pm

    Am surprised the recommendation for water under pebbles persists. After seeing the inevitable algae on the stones, it occurred to me that a dish or 2 of water next to the pot(s) is just as effective (probably more given exposed surface area) and no algae. If it gets grungy, toss it or wipe it off – much easier than scrubbing pebbles!

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