Many plants in our gardens and homes are guests; they are visitors from another climate that we've brought into our environment. With preparation, many garden guests can survive the cold, wet winter outdoors alongside their native cousins. Indoor plants, whether tropical, local native or garden visitor, need special attention to get through the hot, dry winter indoors. Your winter hospitality to both will save spring trips to the nursery.
Bed Them Down
Use the last warm, sunny days and cooler nights of summer to cover perennial toes with a thin mulch layer of marsh hay, burlap or chopped-up oak leaves. Add a second, thicker layer after the first week of hard freeze. Wait to cover plants like roses until after winter is in full swing to make sure they have gone properly dormant. Trim shrubs or roses so they are shaped up for spring blooms, but wait until late winter or early spring to prune most trees and shrubs. Cut back herbaceous perennials to make their bases less hospitable to rodents who might find them a good place to hibernate. Feed the compost bin, but don't add diseased or infested plant matter. It will continue to "cook" over winter and would provide a warm home for pests and viruses. Check with your local university extension to find out whether there are plants that might survive better under a cold frame or plastic dome.
Invite Them In
Many summer bulbs and corms like gladiola, dahlias and canna lilies can be dug, roots and all, and stored in a paper or burlap bag of perlite or peat moss in a cool (40 to 50 degrees F), dark place until planting time in spring. Bring potted geraniums and coleus that graced the summer porch in for the winter, if you're willing to invest some effort in their care. Any plants that are to grow indoors must come in before the indoor heat goes on in the fall, to minimize the shock due to drier air and lower light levels. Avoid bringing pests in by spraying plants with a forceful shower or insecticidal soap before taking them inside. Keep plants together on a tray in the sunniest window (usually east- or south-facing) until they acclimate. If plants tend to grow toward the light and get "leggy," pinch them back midwinter to keep them compact and to encourage branching. Prune all outdoor plants back in late winter so they will be ready to "take off" when it's time to move them outside.
Most house plants and plants that are brought in are tropical plants. They require more light, warmth and humidity than is found in any home north of Naples, Florida. Invest in a humidifier; your plants will prosper and your nose and eyes will feel better due to the airborne moisture. Use cotton shoelaces to make wicks when re-potting; string the shoelace through the drainage hole and up through the root system in the pot. Put pots on trays of pebbles and keep water in the tray to provide constant moisture and humidity, but don't let pots sit in water. Watering through the bottom of the pot also encourages root growth. Limit fertilizer to a half-strength feeding in fall and again in early spring. Don't feed plants during winter---it's their dormant period. Treat plants to their own "rain forest" in the shower stall a few times each winter.