January Tips
TREES, SHRUBS AND GROUNDCOVERS

Contact: Diane Relf, Extension Specialist, Environmental Horticulture

October 1996

  • Examine the limb structure of your shade trees. Remove dead, diseased, and storm-damaged branches. If left on the tree, these weakened limbs can cause damage by falling on buildings or passers-by.

  • Assess the energy efficiency of your landscape. Do you have evergreen trees or shrubs blocking a window where the sun's warmth would be welcome? Consider replacing them with a deciduous plant that would let sun in during the winter, but cast cooling shade in the summer.

  • On mild winter days, remember to water window boxes or other outside containers planted with evergreens.

  • Fertilize broad-leaved evergreens in the winter or spring. Fertilizing in the late summer induces late-season growth that is susceptible to winter injury.

  • For a unified look in the landscape, construction materials and plant materials should be harmonious. Coarse-textured plants, such as rhododendrons, go better with cut stone, rock, and rustic materials. Finished woodwork and brick work well with fine-to medium-textured landscape materials, such as astilbe or artemisia.

  • If grown in good garden soil with adequate drainage, yews will grow in shade, withstand almost any exposure, and resist most pests. Direct sunlight and strong winds may injure foliage in winter in the colder parts of the state, as will the summer heat in the Tidewater area. Keep yews well watered to avoid winter browning of foliage.

  • Looking for plants suitable for containers with roots capable of withstanding very cold winter temperatures? Try wintercreeper, white spruce, shrubby cinquefoil, yews, English ivy 'Baltica,' Vinca minor, creeping and shore junipers.

  • For large shade trees needing removal of storm-damaged limbs, call an arborist or tree surgeon now to get on their schedule for pruning while the trees and underlying landscape plants are dormant.

  • Check guy wires on trees planted in the fall. Stakes may need to be resecured if they have been heaved out of the soil by frost. Remember to remove guy wires in spring after root growth has started. Trees move with the wind grow stronger than those supported for too long.

  • During winter thaws, water fall planted and established evergreens, especially those on the south and west sides of the house.

  • During the short days of winter, landscape ornamentals with striking silhouettes draw attention. Try corkscrew willow, kousa dogwood, weeping cherry, and ornamental grasses. Consider placing one of these where it can be seen from a west window at dusk.

  • Winter is the time to apply miscible oil sprays to kill overwintering mites, aphids, and scale on deciduous trees and shrubs. Spray miscible oils when temperatures are above 40 F, but not within 24 hours of a freeze. Because the oil kills insects by suffocation, avoid spraying on windy days to ensure that all surfaces of the plant are covered.

  • When choosing a location for new shrubs and trees, remember spots that are sunny in the garden now may be shady in the spring or summer. Ornamentals, such as azaleas, camellias, dogwood, mahonia and leucothoe, prefer shade.

  • When using salt to melt ice on walks and drives, spread it carefully to avoid damage to nearby shrubs. Damage to needle-type evergreens will be evident next spring by copper and yellow tones. Damaged deciduous plants will have bronze or reddish leaves. Consider using sand or sawdust instead.

  • Stamp down snow near young trees to discourage mice from nesting under the snow around them and damaging the roots or bark.

  • Remember, trees and shrubs have an economic value. If killed or damaged by ice or accident, they may be covered by homeowner's insurance.

  • Tree branches that cast excess shade over herbaceous flower beds should be removed in winter when they will not damage the bed as they fall.

  • Brush snow from evergreens as soon as possible after a storm. Use a broom in an upward, sweeping motion. Serious damage may be caused by heavy snow or ice accumulating on the branches. Prop up ice covered branches and let the ice melt rather than try to remove ice from brittle branches.

  • In the colder parts of the state, construct wind breaks around plants predisposed to winter damage, such as broad-leaved evergreens. Drive four wood stakes around the plant, wrap with burlap, and staple at each corner. Consider moving these plants to a more protected site in the coming months.

  • Don't delay planting a live Christmas tree, especially if it has already been in the house three days or more.

  • Borderline hardy plants, such as aucuba, camellia, and gardenia, can be protected by a mound of soil or compost placed over the crown after the ground surface freezes. These may also require windbreaks or screens.

  • For added security around the home, plant thorny shrubs on property lines and under windows. Some very thorny ones to consider include pyracantha, tri-foliate orange, Rosa rugosa, and thorny elaeagnus. Order plants now for late-winter planting.

  • Look at your landscape. Do you need evergreens to protect your privacy, reduce street noise, block the glare of street lights? Order plants in January and February for March planting.

  • Some plants that should be pruned in later winter or early spring are hydrangea, butterfly bush, Rose-of-Sharon, hibiscus and other summer-flowering shrubs that flower on new growth. Prune spring-bloomers, such as azaleas, right after they flower.

  • When pruning large limbs, always undercut first. This means to cut from the bottom up, one-third of the way through the limb, then finish by cutting from the top. The undercut keeps the limb from splitting and breaking off, which could damage the trunk and become an entryway for insects and diseases. Do not cut flush to the trunk, the collar or enlarged base of a branch produces hormones that help heal wounds.

  • Seeds requiring stratification, such as many of the woody ornamentals, should be started to condition now. Plant them in your cold frame or put them in your freezer for the required amount of time.

  • Vines that are strangling trees, such as bittersweet, wisteria, wild grape, poison ivy, Virginia creeper, and Japanese honeysuckle, should be cut off and removed.

    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.

    Visit Virginia Cooperative Extension