With the onset of winter, leaves have long since fallen and you can easily observe the “bare bones” of the garden. This is the ideal time to walk around your landscape and note what changes or improvements you would like to make next season. And while you’re taking a critical look at your landscape, don’t forget to tackle any gardening chores that remain undone.
- Look for areas in your landscape where water collects after long periods of rain or snow. Water that collects on the surface of the soil during winter will freeze and can damage perennials. As a temporary solution to this drainage problem, dig shallow trenches to help drain excess water away from the planted area. In spring, consider improving drainage by aerating the soil or raising the beds by gradually adding soil as a top dressing. For more information, see this Northern Virginia Soil and Water Conservation district article on solving drainage problems.
- Loosen or remove thick layers of matted leaves from perennial beds that might prevent moisture from penetrating into the soil or, conversely, hold too much moisture in the soil.
- Continue watering recently planted trees and shrubs. This is particularly important because lack of moisture during long, dry periods in fall and winter can cause injury or death to plant root systems.
- Look for cool-weather weeds in garden beds. It may be December, but lots of weeds can be found growing in the garden at this time of year. Common chickweed, henbit, purple deadnettle, and other “winter weeds” sprout in mid to late fall. Weather permitting, pull the weeds now if you can reach them. A little effort now means less weeding needed in spring. As you weed, try to avoid stepping into flower beds because that can compact the soil.
- Check to make sure mulch is not touching tree trunks. If it is, pull the mulch away from the trunk to prevent moisture from being trapped against the bark. Otherwise, the prolonged moist conditions can decay the bark and, in time, eventually damage or kill the tree. For guidance on mulching, see the Virginia Cooperative Extension’s (VCE) publication on mulching.
- Before the first winter storm occurs, check to make sure you have a good supply of sand or sawdust on hand to put on icy walkways near plantings. Some plants are sensitive to de-icing salts, and sand or sawdust are better alternatives to use for this reason.
- After the ground freezes, check for plants that have been displaced due to soil heaving and replant them. This is a common occurrence with plants that were newly planted in fall and haven’t had sufficient time to anchor their roots into the soil. Make sure the roots are well covered with soil and mulch to protect them from freezing temperatures.
- If you didn’t remember to do this earlier in the fall, drain all water hoses and store them in a garage, garden shed, basement, or other suitable place out of the weather. Also, don’t forget to drain irrigation systems and non-frost-proof outdoor faucets.
- Store concrete bird baths, planters, rain gauges and other outdoor ornaments that might collect water and break in freezing temperatures.
- Clean garden tools with steel wool or a stiff wire brush, wipe with a damp cloth, dry, and apply an oil such as cooking oil, boiled linseed oil, tung oil, or WD 40.
PREPARING YOUR LANDSCAPE FOR SNOW
If a heavy snow or ice storm is predicted, take precautions to prevent damage to your evergreen landscape plants. Species with multiple leaders are susceptible to snow and ice damage. The branches of Leyland Cypresses, in particular, are bad about splaying under a heavy snow load and the damage is generally permanent. Other evergreens that might also be damaged include arborvitae, upright junipers, yews, magnolias, boxwoods, and some hollies. Minimize damage by loosely encircling the outside of the plant with jute twine, narrow rope, or strips of cloth so that individual branches can’t catch and hold much snow. Another technique is to tie the main leaders together, high up on the side of the shrub. The bindings may be left in place once the snow melts or until new growth begins in spring.
Clemson Cooperative Extension’s Publication on protecting evergreens from ice and snow damage recommends preventing storm problems in the first place by selecting evergreens with a single trunk or leader. Species with multiple leaders should be pruned to a single trunk or leader when the tree is young.
WINTER HOUSEPLANT CARE
Overwintering plants indoors needn’t be all that challenging. It’s simply a matter of understanding their requirements for water, humidity, temperature, and light. If you ignore these essentials, you’ll find that it’s quite easy to kill a houseplant. Let me count the ways:
- Overwatering (also known euphemistically as “killing with kindness”) – This is perhaps the most effective way to kill a houseplant. Overly saturated soil prevents the plant from taking up oxygen at the root level. Symptoms of overwatering include wilting and yellowing of the foliage. The proper way to water a houseplant is to give it enough water so that it drains from the bottom of the pot. Otherwise, salts in the water may build up in the soil, which will eventually harm the plant. Unless your plant is one that prefers consistently moist soil, like an African violet, allow the soil to dry out somewhat between waterings.
- Lack of humidity – The flip side of overwatering is not having enough moisture in the air. Once we turn the heat on in our homes, the humidity in the air drops to well below 50%, which is the moisture level that most plants need to stay healthy. Browning of the leaf margins or tips generally indicates that the air is too dry. To remedy this problem, place the houseplant in a bathroom or kitchen where steam from showers or from boiling water will raise the humidity level in the room. Or, if you have a humidifier, try to position it near your houseplants. Another solution is to fill a pebble tray with water and set the pots on top of the pebbles so that they are not actually touching the water.
- Exposure to direct heat – Avoid placing houseplants near a vent or other source of direct heat. Hot air blowing on a plant can severely dehydrate it. An overheated plant will appear very limp.
- Exposure to cold air – If your house is not well insulated or sealed against cold drafts, your plant can suffer from exposure to the cold temperatures. You’ll have the same problem if you place a tender tropical plant near a door that is opened frequently.
- Direct contact with a window – Although most houseplants need as much light as possible, don’t let them have direct contact with a frosty window. Otherwise, the foliage touching the glass may freeze.
- Not enough light – Plants that aren’t getting enough light will look pale rather than a healthy green color. New growth will look tall and leggy or spindly and the new leaves may appear smaller than normal. To solve the problem, move the plant to a brighter spot, preferably to a south or west-facing window. Give the plant a quarter turn once a week so that it grows evenly and doesn’t lean or stretch toward the light.
- Pest problems – It may be wintry outside but that doesn’t mean plant pests aren’t an issue. Pests such as white fly, spider mites, aphids, mealy bugs, and scale can multiply very quickly on plants. Inspect your plants frequently for unwanted hitchhikers and deal with them promptly. For more information on houseplant pests, see Clemson Cooperative Extension’s publication on common houseplant insects.
The holiday season is a great time to share rooted cuttings from your houseplants with friends and neighbors. Plants make wonderful “hostess” gifts and are a nice alternative to sugary sweets or scented candles. If your friends are (gasp) not “plant people,” they’ll appreciate your thoughtfulness if you include a few plant care instructions with your gift. As an aside, if you have never propagated a houseplant, then check out the University of Missouri Extension’s article on home propagation of houseplants. It provides straightforward instructions and excellent photos to illustrate the propagation process.
DECORATING FOR THE HOLIDAYS
Celebrating winter holidays in December generally means decorating the house with greenery.
- Cut Christmas Trees – If you plan on selecting a cut Christmas tree, check out Holiday Decorating with Fresh Greenery, which appeared in the December 2015 issue of The Garden Shed. The article includes a table comparing the four most popular Christmas trees – Fraser Fir, White Pine, Scotch Pine, and Norway Spruce. If you’re not sure which is which, here’s how to tell the difference:
Fir – If the branches bear their needles individually rather than in groups and if the needles feel flat to the touch, the tree is most likely a fir.
Pine – If the needles occur on the twigs in groups of two, three, or five, it’s a pine. To further distinguish between white pines and Scotch pines, white pines have longer, softer looking needles than Scotch pines. Scotch pines have dark green needles and stiff branches that can hold heavy ornaments better than white pines.
Spruce – if the needles have four sides and roll easily between your fingers, it’s a spruce.
- Live Christmas trees – If you buy a live Christmas tree with the intention of planting it in your landscape after the holidays, keep it out of doors until you’re ready to decorate it. Make sure it stays well watered and doesn’t dry out. Once you move the tree indoors, keep it in a cool room for a few days only. As soon as possible, move it back outside and continue to keep it well hydrated until it can be planted in a permanent spot in the landscape.
- Poinsettias – These cheery tropical plants are a colorful way to decorate for the holiday season. However, they can rapidly wilt if not properly cared for. To keep poinsettias looking their best, pay attention to their light, water, and room temperature requirements. They prefer bright filtered light, but will also thrive in a sunny, south-facing window. Water regularly but check to make sure the water drains away from the roots. They like evenly moist but not soggy soil. Prolong the display by keeping the indoor temperature at about 68°F during the day and cooler at night.
- Evergreen Wreaths – If you’re planning to use a freshly cut or ready-made evergreen wreath, store it in a cool location until it is ready to be decorated. Soak it in warm water for several hours to keep it moist. Drain it well and then spray it with an anti-desiccant spray to seal in the moisture. After the sealer has set, finish decorating the wreath and hang it, preferably in a shady place that doesn’t receive sun.
- Boxwood Decorations – If you purchase ready-made wreaths, swags, and other decorations that contain boxwood clippings, inspect the clippings for symptoms of boxwood blight (Calonectria pseudonaviculata). Symptoms include leaf spot, leaf drop, browning, or black streaks on stems. Although reputable suppliers of holiday greenery are taking precautions to avoid spreading this disease, it pays to be cautious. After working with boxwood decorations, sterilize garden tools with alcohol or a chlorine bleach solution. Once the holidays are over, bag the decorations for disposal in the trash. Do not compost them. The VCE publication on boxwood blight provides more information on this disease.
- Pets and holiday greenery – Keep pets away from holiday plants such as poinsettias, mistletoe, and holly. Ingesting poinsettia foliage is not normally life threatening to pets, but the sap can cause mouth and stomach irritation as well as vomiting. Also, if the plant has been treated with a pesticide, the chemicals in the pesticide may cause more serious medical problems for a pet than ingestion of the sap. Mistletoe and holly berries are more toxic than poinsettias and can cause more serious health problems for pets.
INVASIVE PLANT CONTROL
Now that leaves have long since fallen, winter is an excellent time to identify invasive plant species. Many of them are evergreen and easy to spot. This is also a good time of year to treat invasives, particularly if you are using an herbicide. There’s less risk of accidentally damaging native species that are dormant and protected by leaf litter. For more information on invasives, see the Blue Ridge Partnership for Regional Invasive Species Management’s (PRISM) article on identification and control of invasive plants in winter. See also the Invasive Plant Control Calendar in the May 2022 issue of The Garden Shed.
Featured image: Holiday centerpiece composed of gathered plants. Photo: Cathy Caldwell
