December Tips
PERENNIALS, ANNUALS AND BULBS

Contact: Diane Relf, Extension Specialist, Environmental Horticulture

October 1996

  • Tender plants in perennial gardens benefit from a light covering of evergreen boughs or oak branches with their leavesintact. The purpose of this covering is to lessen desiccation ordrying out by wind. Take care not to smother the plants. You should be able to see the plants through the branches.

  • If outdoor plants dry out during the winter, the foliage can be damaged. Water plants in late summer and fall, especially if rain has been less than normal, and on warm winter days if soil is dry.

  • If stored bulbs begin to shrivel, they are too dry. Place them in a container with potting medium, peat moss, or sawdust to stop the loss of water.

  • To avoid harming near-dormant plants during the winter, do not fertilize, and reduce watering until growth resumes in the spring.

  • A light covering of hay or leaves over perennials inside the cold frame gives added protection from low temperatures and bright sunlight.

  • Bulb forcing can be started as late as mid-winter. Plant tulip bulbs with the tops just above the soil line and the flat side of the bulb toward side of the pot. Plant daffodils with the bulb tops even with the soil line. Hyacinth bulbs should be planted with the tops just above the soil. Crocus bulbs should be planted about 1 inch below the soil surface.

  • Mums and pansies tend easily to be heaved out of the ground during weather freezes and thaws, causing root damage. Place discarded Christmas tree branches over flower beds to prevent this from happening.

  • Use branches from discarded Christmas trees to mulch beds of bulbs.

  • Mulch perennial borders after the ground freezes to a depth of a two or three inches. Applying mulch too early increases the chance of harboring destructive field mice that are still on the lookout for comfortable winter quarters.

  • Sow seeds of alpine plants early in December in an outdoor coldframe. Ideally, the seeds should remain frozen until March, then germinate in spring, so the frame should be kept shaded and ventilated. Seeds also may be sown in flats and placed in some convenient, shaded, outdoor location where they will stay frozen until spring. A good covering of snow seems to help.

  • Winter protection for peonies is necessary only the first winter to help prevent frost heaving. Mound soil over the new planting for several inches, or after the ground freezes hard, mulch with evergreen boughs or straw. Don't use a material that will mat down, such as leaves. In extremely cold climates, 10 to 20 degrees below zero, protection also is necessary for tree peonies.

  • Check dahlia tubers and gladiolus corms in storage. If they are sprouting, place them in a cooler spot. If they show signs of shriveling, rewrap them in ventilated plastic bags. Moldy or damaged roots must be removed and discarded. Molding indicates over-moist conditions. Move healthy bulbs to a location with better ventilation, and set in dry peat moss.

    Monthly Tips have been prepared since 1986 by various staff of the Office of Consumer Horticulture including Ellen Bennett, Michelle Buckstrup, Susan Day, Susan DeBolt, Sharon Dendy, Kate Dobbs, Sheri Dorn, David Gravell, Virginia Nathan, Jenny Shuster, Ellen Silva, and Ruth Sorenson. Resource material for the development of this information includes the Virginia Master Gardener Handbook; Extension Publications and newsletters from VCE, numerous other states, and the USDA; and an extensive library of over 900 books, magazines, and journals. Project funded by The Virginia Gardener Newsletter subscription fees. Diane Relf, Project Director and Content Specialist.

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