University of Vermont Extension 
Department of Plant and Soil Science

Winter (Holiday) News Article
Charlie Nardozzi, Horticulturist and
Leonard Perry, UVM Extension Horticulturist
Giving your holiday plants the proper care for longest life, caring for geraniums indoors, and watching for spider mites are some of the gardening activities for this month.     
Decrease water and fertilizer on Christmas cactus if the buds are developing. To prolong the colorful bracts on poinsettias, keep them where temperatures don't exceed 70 degrees (F)  during the day or drop below 65 degrees at night.  Also keep poinsettias out of drafts, and don’t overwater.  Kalanchoe, with their brightly colored flowers, have thick, succulent dark green leaves.  Given warm and dry conditions and soil, and bright light, they’ll last for weeks.
Keep potted amaryllis in a cool (60 degrees) shaded location until buds open. Then move it wherever you like. Cyclamen prefer cool temperatures, too, so keep them back from south-facing windows that heat up during the day.  Cyclamen also prefer even moisture, so don’t allow to wilt and definitely don’t keep too wet or they may rot.
Paperwhite narcissus are a popular bulb to “force” for the holidays, if you don’t mind the fragrance.  Unlike other daffodil relatives, these don’t need cold to flower.  Simply pot, give cool if possible until shoots start (50 to 60 degrees at night is ideal), then give more warmth.  Too much warmth and shoots may get top-heavy and need staking. 
To pot paperwhites, as with other bulbs, keep the tips at or above the soil level.  Use a bagged houseplant soil, with three bulbs in a pot 6-inches across.  Or, you can place bulbs half buried in a pot of white gravel to hold them.  For the latter, use a pot or vase with no drainage holes.  Keep water in the bottom, but make sure the bulbs aren’t continually submerged in water.
African violets make great houseplants and will flower in winter if given supplemental light. To propagate new plants, take a leaf cutting, dip the cut end in a rooting hormone powder (from a garden store), and stick the cutting in a pot filled with vermiculite, perlite, or sand. Cover the pot with a perforated clear plastic bag and keep the soil moist. In a few weeks you'll have new plants.
If you brought in your geranium plants this fall and are growing them indoors this winter, chances are they've become leggy. The cloudy, short days of November and December don't provide enough light for these plants to thrive. Cut back the plants to about 1 foot tall. They will resprout and grow bushier in the longer days of late winter.
The warm, dry indoor air in winter is prime breeding ground for spider mites on your houseplants. Look very closely at the undersides of leaves, at the base of stems, and on new buds for fine webbing.  Another sign of such mites is leaves that are finely speckled.  Looking underneath with a magnifying glass you’ll see their webbing and them moving about if present.  Set any suspicious-looking plants in the shower to wash off the mites, and repeat frequently. Insecticidal soap also works, but it's smelly to use indoors.
You can help increase the humidity around plants by misting with one of those water misters as you find at hardware stores.  This may harm furniture though, so an alternative is to place plants on a tray of pebbles, and keep them moistened whenever you water the plants.
Other gardening activities for this month including shopping for gifts for gardeners at local garden outlets or online, visiting a cut-your-own tree farm for Christmas tree or other holiday decorations, hanging suet blocks for birds and keeping bird feeders filled daily.

(Charlie Nardozzi is a nationally known horticulturist, author, gardening consultant, and garden coach; 

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