December Gardening Tasks
Vegetables - The winter is a great time for growing things like mustard greens, turnips and turnip greens, collards, cabbage, broccoli, spinach, beets and such. Pine needles, straw mulch, floating row covers, and small garden hoop covers, can all be used to extend the growing season to at least the end of December.
Lawns - Pick up fallen leaves, limbs, and other debris from lawns to prevent suffocation of the turf during winter. Store any leftover lawn fertilizers in a dry location and out of reach of children and pets. Seal the bags to keep moisture out! Store pesticides and fungicides in a cool (not freezing), dry location for winter, out of reach of children and pets.
Trees and shrubs - Check and protect the trunks of young trees and branches of shrubs for rabbit or squirrel damage. Prune damaged branches throughout the winter months. Water newly planted trees and shrubs in winter as needed to prevent dry soil conditions. Prune branches of junipers, pines, hollies, and other plants to use as holiday decorations.
Mulch roses by mounding soil 6 to 8 inches deep over the plants to protect the graft (Don’t prune until February). The winter months, when trees are dormant, are excellent times to plant. Be careful that you do not plant them too deeply. Be sure to plant no deeper than the tree in its pot or root ball and make sure there’s a beginning root flare at the base of the trunk. Don’t backfill tree planting holes with organic matter as it will shrink as it dries, but use native topsoil and be sure you’re generous with topsoil backfill especially near the surface!
Don’t prune cold-damaged plants yet. Wait until warm weather returns to cut back plants.
Fallen leaves provide the carbon ingredient needed for successful composting and also make a good mulch. Turn compost piles to encourage winter breakdown.
Now that temperatures are lower, use dormant oil sprays to control scale insects on trees and shrubs.
Flowers - Mulch perennial beds with 2 to 4 inches of straw, shredded leaves, or other lightweight material. Empty decorative ceramic pots and containers and store in a storage shed, garage or carport for winter. If unusually cold weather is predicted, mulch and protect ornamental cabbage, kale, pansies, snapdragons and other cool-season outdoor plants.
If you haven’t done it, make sure you plant those spring-flowering bulbs you purchased earlier in the fall, such as daffodils, tulips, hyacinths, and crocus. Enjoy the winter color from plants like pansies, snapdragons, ornamental cabbage and kale, hellebores, camellias, and such.
Fruits trees - Be sure to inspect your fruit trees. Remove any mummified remaining fruits, and rake up and dispose of old leaves and branches that may harbor diseases over the winter.
Now that temperatures are lower, use dormant oil sprays to control scale insects on fruit trees and shrubs.
Seed catalogs - Now is a good time to pour through the seed and plant catalogs and online seed sources for new varieties. Make sure what you buy will thrive in our hot and humid zone 7b-8a climate! To be certain you can get what you want, make early seed orders now.
Houseplants – To keep holiday plants looking good longer, keep them away from dry, drafty locations. Do not place near heat vents, doorways or drafty windows. Increase humidity around plants by placing them on a tray lined with pebbles, shallowly filled with water. Make sure the water does not enter the drainage holes. Winter is a challenging time for most houseplants because of the lower natural light and susceptibility to over watering. Be careful not to over-water houseplants. Growing media should be allowed to nearly or completely dry out between watering (but plants should never wilt). Unless your indoor plants are growing under optimum, high light conditions and are actually growing, do not fertilize them during the winter months.
Inspect indoor plants regularly for pests, especially ants, spider mites, aphids, white flies, scale insects and mealy bugs. Keep in mind that plant-specific temperature, light, and humidity are key to ensuring that indoor plants thrive.
Amaryllis is a popular plant for the holiday season. They can be forced to bloom now or planted outdoors for spring blooms.
One of the most popular indoor holiday plants is poinsettia. With proper care, this colorful plant will give weeks of color. Call the Hall County Extension Service for advice on after-holiday care for poinsettias.
Miscellaneous - If flower or vegetable plants did not perform as desired this year or new plantings are being planned, a soil test may be a good idea.