Garden tasks for December
by Mary Robson, WSU Extension Agent
If you have family members visiting from the frozen Midwest or the snowy East during the holidays, they may be surprised to find that gardening continues during winter in the Maritime Northwest.
If we bribe the visitors with holiday cookies, will they join us in the garden?
Rake leaves from grass and ground covers. Fertilize the lawn if it didn't get done in November, using a 3-1-2 ratio fertilizer and applying about 1 pound of actual nitrogen per 1000 square feet of lawn.
Turf experts say the late fall fertilizing is the most important of the season in this area, helping to get the lawn through winter in a healthy condition.
Shrub plantings under deciduous trees also need raking. Leaves can be added to compost piles, or used as mulch.
Admittedly, it's strange to rake leaves off the garden and then redistribute them as mulch. However, foliage of lawns and landscape plants must be cleared of fallen leaves.
Completing weeding and transplanting, then adding mulch, does carry a sense of "tucking the garden in for winter," which is satisfying to maternal and paternal instincts.
Use smaller leaves for mulch (birch, small maples, hornbeam), or run a power mower over larger ones. Big leaves, such as walnut or bigleaf maple, will pack down and do not work well as garden mulches unless shredded or composted for a year or so.
Keep compost piles covered with lids or tarpaulins during winter rains for best composting.
Clear vegetable gardens of all dead foliage; if the garden will be fallow until spring planting, pile leaf mulch over it to keep down winter weeds. In spring the leaves can be dug in if they have started to decompose, or removed to a compost area.
Vegetable gardeners with the urge to plant can still add garlic bulbs to gardens. Garlic needs a well-drained soil and plenty of sun. It's one of the satisfying crops that really gives a return on investment, as small separate cloves should head up into bulbs by the time of summer harvest. Plant them about three to six inches apart and about two inches down.
An old folk saying about garlic is, "Plant on the shortest day, harvest on the longest day." Here the garlic will not be ripe by June 21, but the saying does convey the rhythm of garlic planting.
If the vegetable garden hasn't been limed for the past three years, add dolomite lime now. "Dolomitic lime" contains magnesium as well as calcium carbonate and will help to add some magnesium to soils. Most vegetable crops do best in a pH range of 6.0-6.5, and lime will help bring soils up to that level.
Add five pounds per 100 square feet of garden, digging it in well. In very heavy soils, add eight pounds per 100 square feet. And in sandy soils, add four pounds per 100 square feet every two years rather than every three years.
Dolomite lime needs at least three to four months to affect garden soils and should be added now to get the best results before spring planting.
Clean up all fallen fruit or diseased leaves from apple, pear, plum, and other fruit trees.
If odd-looking "mummified" fruit remains hanging on plum or other stone fruit trees, get into the tree and remove it carefully. These dried-looking fruits carry spores of the fungal disease called brown rot that infects next year's crop as the tree begings to flower and leaf out.
Early to mid-December is the "last call" for planting spring-flowering bulbs. Retrieve those forgotten bags of narcissus, tulips, crocus, and hyacinths.
Spring bulbs require 11 to 12 weeks of cold underground temperatures before they are ready to send up shoots and flowers. Nurseries often have bulbs on sale this month; check for bargains and plant now.
Another good project with spring-blooming bulbs is to plant them in containers and present them as gifts. Containers can be wood, plastic, or even ceramic (high-fired to take the weather). Be sure they have clear drainage holes.
Bulbs in containers go at the TOP of the container, not at the bottom. The idea is to leave plenty of room for roots.
Fill the container with any good gritty potting mix, about 3/4 full. Water it well. Then put the bulbs in, about one inch apart. Cover with the remaining 1/4 potful of soil and water again. Label the pot.
To present it as a gift, cut out a catalogue photo of the plant in bloom and include instructions to leave it outdoors in a sheltered spot until early spring.
Bulbs in containers need the same cold period exposure as bulbs in the ground do, and they should be either insulated with leaves or other mulch or buried in the ground to prevent freezing in extremely cold weather.
Do not prune roses now. Cut back or tie any longer canes to keep them from whipping around in wind; prune in late February. Leaving the woody structure of the plant intact helps to protect the rose from winter freezes.
Remove all the leaves to force the plant into dormancy. Cover the bud union (the swollen part at the bottim of the stem just above the roots) with any organic mulch as part of winter protection.
Keep houseplants lightly watered. Don't fertilize established older houseplants during dark winter months while they are not growing. Clean the leaves and provide as much light as possible.
Gift plants such as poinsettias, chrysanthemums and cyclamen need good light and protection from drafts. Remove the decorative wrappings or poke holes in the bottom of them. If the plant is tightly wrapped in foil or plastic, standing water can accumulate next to the roots and cause root rots. Be sure to provide drainage!
Take some time to review the landscape and evaluate what's been satisfactory and what needs changing. Visit the nursery and look for winter-blooming plants like sarcococca and winter hazel. Walk in a local park or arboretum to get planting ideas. And request plants as holiday gifts!