Dormant roots of asparagus are available now in some nurseries. Consider male-only plant varieties for greater harvest.
Continue to set out cool-season bedding plants such as pansies, violas, stock, snapdragons, dianthus and ornamental kale.
Don’t forget tulip and hyacinth bulbs in the refrigerator. They can be planted any time in December.
If you’re planning on indoor color this winter, it’s time to force those bulbs you’ve been chilling. Get them moved into a warm area of the house so they’ll be tricked into thinking that spring has arrived. They’ll start putting out leaves and developing buds so you’ll have a rush of beautiful color later this month. To keep the color coming, stagger your potting cycle so everything doesn’t bloom at once.
Plant living Christmas trees in the ground as soon as possible after the holidays.
Plant trees and shrubs, taking care not to plant them too deeply. Always plant them at the same level as the root ball.
Prepare beds and individual holes for rose planting in January and February. Use composted manure, pine bark and similar materials mixed with existing soil.
Rather than leaving your beds bare, consider sowing cover crops such as winter rye and hairy vetch that will improve soil fertility and texture, cut down on erosion and weeds, and provide ample mulch material when you chop them down in spring.
If the soil is acidic, your landscape probably could benefit from an application of lime. Get your soil tested and be prepared for spring.
Holly plants with a heavy set of fruit often suffer a fertilizer deficiency. An application of complete fertilizer late this month can be helpful and provide a head start next spring.
Mow the lawn for the last time to eliminate stragglers, and dethatch if necessary to remove any dead grass. Apply a final coat of low phosphorus fertilizer to tuck it in for winter.
Treat azaleas, gardenias and camellias with chelated iron if leaves were yellow between the veins.
Berrying plants such as holly and yaupon may be pruned now while they can be enjoyed as cut material inside the house. Use good pruning practices when selecting Christmas greenery from landscape plants. Don’t destroy the natural form and beauty of the plant.
Don’t spare the pruning shears when transplanting bare-rooted woody plants. Cut the tops back at least one-third to one-half, to compensate for the roots lost when digging the plant.
Now is a good time to take hardwood cuttings.
Wait until the end of this month to start pruning woody plants as necessary. This chore should be done while the plants are dormant – likely to be late December through February.
Stone fruits such as cherries, plums and peaches are prime for pruning in December.
Prune outdoor limbs or branches that have been damaged by winter storms. The damaged parts should be removed immediately. Remove suckers and water sprouts, too.
Remove older canes of blackberries.
Frost has killed back the top growth of most of our favorite perennials and they can now be pruned nearly to the ground. The tops of others are still green, and they don’t need to be completely trimmed back. Just a general cleanup of any brown foliage is necessary there.
Drain and store garden hoses and watering equipment in a readily accessible location. The lawn and plants may need water during a prolonged dry spell.
If you need to use a hose frequently in the winter and find all the connecting and disconnecting troublesome – especially when your fingers are freezing, attach a quick-connect fitting between the tap and hose. The fitting can be left in place all year.
If your automatic watering system stays on all year, it’s time to adjust the amount of watering during each cycle. Many dormant plants require lower amounts of water in colder months. A good rule of thumb is to reduce irrigation time by half when night temperatures remain in the 40s or below. Turn the system off in rainy periods to reduce costs and prevent overwatering.
Fix any dripping outdoor faucets and then wrap the exposed portion of the water pipes. Insulation that becomes saturated from a leaky faucet is of little protective value during freezes.
Turn off and drain sprinkler systems by removing the head from the sprinkler at the lowest point of your lawn or install a sprinkler end drain.
Watch for dry, windy conditions with low relative humidity that can damage turf. It may be necessary to irrigate periodically to help the grass survive.
Remember, plants need water during the winter and well-hydrated plants withstand freezes better; water when the top inch of soil is dry.
Check the soil moisture of houseplants. In general, don’t water until the soil is dry an inch or so from the top. Overwatering is the biggest risk in winter … go easy.
Check overwintered plants in the basement and garage to check for possible water needs.
During dry and frozen times, fill the birdbath. You don’t have to haul out the hose; just fill a pitcher with water. Some gardeners invest in birdbath warmers to keep the water from freezing.
Now is a good time to reduce the insect and disease potential in next year’s garden. Clean up the garden, removing all annuals that have completed their life cycle. Remove the tops of all herbaceous perennials that have finished flowering or as soon as frost has killed the leaves.
Apple, peach, pear and plum trees need to be sprayed regularly. There are different sprays to be applied at various times throughout the cool months, so be sure to check with your local Co-op store about when to spray your fruit trees to keep them healthy.
Brownish specks at the tips of camellia petals or brown dead centers at the base of petals can indicate petal or flower blight. Remove and destroy infected flowers, including fallen blossoms; also remove the mulch beneath the shrub. Treat with a fungicide. Enrich the soil and strengthen the affected plants by adding compost to the growing bed.
Clean up piles of bricks, stones, wood or other debris that can serve as insect-breeding and overwintering sites.
Watch out for snails. Hand pick or treat accordingly.
Apply broadleaf herbicides to control winter annual and perennial weeds in your lawn. Use only as directed.
Watch out for signs of houseplant pests like spider mites, mealybugs and scale insects. If tackled before they get out of hand, nonchemical methods are usually successful: a simple shower, insecticidal soap spray (as directed on label) or, with the most tenacious (like mealybugs), sometimes an alcohol swab and Q-tip.
Don’t store firewood in the house as insects can come in with it. Leave the wood outside until you are ready to use it. Burn the oldest wood first so that pest populations do not get a head start.
Wish you would have installed drip irrigation this year? Did the wooden handle on your 20-year-old shovel split? Was one plot particularly weedy? Now is the time to make a list of all the things you’ll forget by next spring. What worked or didn’t work in your garden this year? What did you learn? Hopefully you’ve been keeping a gardening notebook or journal so you have information about what you planted, when and how it fared.
Become a Master Gardener! Call your county Extension office for more details.
Give gardening tools and subscriptions to gardening magazines as gifts.
Take some time to care for houseplants. With a wet cloth, wipe the dust from their leaves. Doing this allows your plants to breathe during the time of year when indoor pollution is at its height.
Watch for houseplants with leaves that have brown, dry edges as this indicates low relative humidity in the house. You can increase humidity by running a humidifier, grouping plants together or using pebble trays. To do this place gravel in trays (in which an even moisture level is maintained) under the flower pots. As the moisture around the pebbles evaporates, the relative humidity is raised.
Living plants that make good Christmas gifts include herbs. Basil, lavender, lemon balm, marjoram, mint, oregano, parsley, rosemary, tarragon and thyme grow well indoors, in a sunny window.
Check bulbs, corms and tubers in store for signs of rot.
Clean and oil garden tools. Your tools have worked hard for you this past year, so do them the favor of cleaning them up before they take a winter’s rest. Clean off any visible debris and dirt, sharpen blades and oil all moving parts. You can purchase sharpening kits at your local Co-op store, or take them to a specialty store to have them sharpened. If your hardware store doesn’t perform this type of task, look for a knife or tool store in your area.
Cut asparagus to the ground and mulch it.
Follow weather forecasts closely to ensure you’re setting greenhouse heating accurately.
If you are planning to save caladium tubers for another year, dig and allow them to dry in a well-ventilated, shady area. After 7-20 days, remove leaves and dirt, then pack in dry peat moss, vermiculite or similar material for storage. Pack tubers so they do not touch each other. Dust with all-purpose fungicide as you pack. Place container in an area where temperature won’t drop below 50 degrees.
If you have saved seeds of your favorite plants, allow them to air dry; then place them in an airtight container and store in the refrigerator. Be sure to label each packet carefully. Remember, seed from hybrid plants will seldom resemble the parent plant.
In dry periods, make a start on winter digging if you have heavy soil. Clay soils will be improved by the action of winter frost after they are turned. Leave light, sandy soils until late winter, but mulch with organic matter to help prevent leaching. Earthworms will help in drawing down organic matter in the intervening months.
Move your garden accessories indoors or cover them with heavy plastic to extend their lives. Freezing and thawing is hard on porous surfaces like cement, terra cotta and plaster, but can be equally damaging to plastic furniture. Move small pots, window boxes and statuary indoors before freezing weather.
Once the plants are trimmed back, take a look at your mulch layer, garden fabric, trellis and garden edging. These items are much easier to replace or replenish in the off-season. Since your plants are dormant, the risk of damaging them if you need a major overhaul is limited.
Prolong the life of holiday-season gift plants by providing proper care. Check to see if the pot wrap has plugged up the bottom drainage. Don’t overwater. Keep out of drafts from heating vents and opening doorways. Fertilizer is seldom needed the first few months.
Repair and treat fencing and timber structures while climbing plants are dormant.
Scoop fallen leaves and rotting plant debris from ponds.
The last of the leaves should have fallen by now. Make sure to remove them from the lawn and either compost or add to your garden beds as mulch.
When you add leaves to your compost bin/pile, be sure to have extra soil available so that each 6-inch layer of leaves may be covered with several inches of soil. Always wet the layer of leaves thoroughly before adding the soil. Add grass clippings, blood meal or a cup of a complete lawn or garden fertilizer to each layer of leaves to provide the necessary nitrogen for decomposition. A sprinkling of dried molasses also encourages microbes to work harder.
If you haven’t set out a bird feeder, do it this month.