December

December Gardening Tips for Los Angeles County Residents
by Yvonne Savio

-- This month's discussion of garden tasks is based on my 60 years of gardening at my home in Pasadena.
-- For my comments on current weather conditions and activities, see my blog page which includes archived blogs since 2015.
-- For my discussions of major gardening topics, see my homepage listing.
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The sun's light and warmth slip to the year's low ebb this month. During warm spells, however, some seeds will germinate, so sowing under protected conditions is worth the effort. These seedlings can fill gaps in the winter garden and continue harvests into early spring. But, plants will grow very slowly, so sow or transplant three or four times the amount you would in the spring.

Fresh-picked chard, lettuce, spinach, and other greens are delicious, nutritious, and far less expensive that what's available at the supermarket. They're worth starting now if only for their flavor and texture added to storebought basics. Besides, it's wonderful to have something bright green growing in the garden all winter--besides weeds.

Vegetables and Fruits

Sow chard, kale, leeks, Bibb and buttercrunch and romaine lettuces, mustards, green and bulb onions, flat-leaf parsley, peas, radishes, and savoy-leafed spinaches. Sprinkle just enough to settle them in.

To help concentrate daytime warmth and increase germination, cover the bed with clear plastic sheeting. Anchor down the edges with soil or rocks to keep out slugs and other critters who love the succulent sprouts, and to keep the sheeting from blowing away.

Transplant globe artichokes, Jerusalem artichokes, asparagus, broccoli, cabbages, cauliflower, horseradish, and rhubarb; also cane berries, grapes, and strawberries. But, do so only when the soil is not waterlogged--if it crumbles after squeezing a fistful, it's ok; if it squishes or stays in a lump, it's too wet.

Planting asparagus at different depths will provide a longer harvest--the shallow asparagus will send up its spears earlier in the season, and the deeper crowns will sprout later.

Harvest leaf crops such as lettuce and spinach by removing only the outer leaves. Let the smaller three or four center leaves develop further. Thus, the plant continues growing--and you continue harvesting--throughout the season until spring warmth causes the plant to go to seed. By then, you'll soon be harvesting spring-sown or transplanted greens to supply your salads.

Protect citrus from cold damage by wrapping the tree trunks in newspaper and covering the foliage with plastic sheeting. Cold soil and dry winds can cause the rinds of ripening fruit to develop bleached blotches, and leaves to turn yellow where the sun strikes.

Plant and tree roots are not very efficient in bringing in moisture during cold weather, so be sure that they get water but aren't waterlogged.

Provide temporary light shade or plastic sheeting to protect the southwest side of the plant from chilling winds. Be sure it doesn't touch the foliage, as this may conduct the frost directly to the foliage and increase damage.

If you missed Thanksgiving's scheduled dormant spray application, spray as soon as possible now. It's always better to apply it late rather than wait for the next scheduled time, for long-lasting coverage. The second scheduled spray, at the "height" or "depth" of the dormant season, can be made anytime from now through mid-January, whenever you can expect several days of dry weather above 40 degrees in temperature. On apricots, use lime sulfur instead of copper.

Prune fruit trees and vines later this month, but only when all of the leaves have fallen. This indicates that the plants are fully dormant, and pruning will not damage living tissue. Don't clip spring-blooming shrubs, however, or you'll remove this coming spring's color--wait till bloom is over. Also wait to prune outdoor fuchsias till they leaf out and you can see just what frost damage actually occurred.

General

Continue to water your overwintering outdoor plants unless the rains keep the soil moist. Irrigation should be reduced, not stopped, as plant photosynthesis slows down and cold weather dries plants out. Plants that are stressed lack of irrigation are more susceptible to frost damage. Water less frequently but just as deeply to assure that the full root systems are hydrated.

Clean up all garden debris, and dispose of it or compost it (not diseased items, however--toss these, don't compost them). Leaving debris in the garden provides harboring areas for overwintering pests. Periodically rough up soil surfaces to bring these pests and their egg cases to die of exposure on the surface--or get eaten by birds!

Cover the compost pile loosely with a tarp or black plastic to hold in heat and keep rain from leaching out the valuable nutrients.

Thoroughly clean, sharpen, and oil tools, and apply linseed oil to wood handles. Store tools in a protected area, as severe weather and moisture contribute to their premature aging.

Provide feeding stations for winter's hungry birds, and keep them well- supplied with seeds, suet, and water; they'll reward you in the spring and summer by eating the garden's undesirable insects.

Make notes on last year's garden while your memory is still fresh. Your initial choices, impressions, and the results of this year's garden will provide a starting point for next year's choices.

Ornamentals

Sow African daisy (gazania), ageratum, alyssum, baby-blue-eyes, baby's breath (gypsophila), bachelor's buttons (cornflower), calendulas, candytuft, delphinium, forget-me-nots, hollyhocks, impatiens, larkspur, lobelia, lunaria (honesty, money plant, silver dollar plant), lupines, nasturtiums, pansies, sweet peas, California and Iceland and Shirley poppies, verbena, and wildflowers. While they may not germinate immediately, they will after a stretch of warm weather, so keep seed flats moist.

Plant more spring-blooming bulbs early this month, and save some to plant from mid-February through mid-March for extended bloom through late spring.

Transplant astilbes, azaleas, bleeding hearts, calendulas, camellias, canterbury bells (campanula, bellflower), cinerarias, columbines (aquilegia), cyclamen, delphiniums, dianthus, forget-me-nots, foxgloves, gaillardias, hollyhocks, lilies-of-the-valley, ornamental cabbage and kale, pansies, peonies, Iceland and Oriental poppies, primroses, snapdragons, stocks, sweet Williams, violas, and violets.

When transplanting, be careful to not compact the soil, now that it's thoroughly cold and moist. After gently gathering the soil back around the transplant's roots, barely water it in--just enough to settle the plant. Tamping the soil more than lightly will damage the soil tilth by compression, making it difficult for roots to penetrate.

Feed shrubs and trees that will bloom in January and February. If azalea and gardenia foliage is light or yellowish-green, water plants with a solution of chelated iron.

If you haven't already, lift begonia, caladium, gladiolus, and dahlia bulbs, corms, and tubers. Let them dry for a day, and gently remove any remaining soil (but don't wash them). They may rot if they are left in heavy, wet soil over the winter. Check stored bulbs, corms, and tubers at least every three weeks, and discard any that have spoiled; if any have sprouted, the storage area may need to be cooler or darker.

Divide dahlia clumps so that each new section retains a piece of the stem, as new shoots will sprout only from that spot. Store them in open containers with good ventilation in a dark, cool but frost-proof place that doesn't get warmer than about 45 degrees.

Protect tender plants from frost. Move dish cacti and succulents and potted trees under cover for protection from cold and rain. For overnight protection when frost threatens, cover bougainvilleas, fuchsias, hibiscus, and other subtropicals with large cardboard boxes; or drape old sheets or tarps on stakes over them. If plastic sheeting is used, don't let it touch the foliage, or the foliage may freeze more readily.

If you plan to decorate a live Christmas tree indoors and then move or plant it outdoors afterwards, choose a smaller size of tree, as it'll adapt better than a more mature one. After you bring the tree home, water it well and store it in an unheated garage or outbuilding for two or three days as a "half way spot" transition area before you move it indoors. Keep the rootball moist and the boughs misted.

Once the tree is in place indoors away from heating vents or fireplaces, either water it directly or by scattering ice cubes around the soil surface to slowly seep down into the entire root ball. Limit its time indoors to a maximum of seven days; fewer if the house is very warm.

Move the tree outside again to the garage, shed, or protected spot for at least two weeks before moving or planting it in the open garden. The longer you enjoy the tree in the warm house, the longer it will need to reacclimate to outdoor conditions.

Prune conifers and broad-leafed evergreens to shape them, lessen chances of wind and frost damage, and provide trimmings for holiday decorations. Branches that hold their shape well indoors include incense cedar, fir, laurel, magnolia, oleander, pine, pittosporum, podocarpus, and viburnum. The red berries from cotoneaster, nandina, and pyracantha always serve as a bright accent.

Norfolk Island pines can become mini-Christmas trees, with their own tiny lights and ornaments. Provide each room in the house with its own individually decorated tree--like cookie cutters hung with red ribbon bows for the kitchen. Other living plants for indoor color include African violets, azaleas, begonias, Christmas cactus, Christmas (Jerusalem) cherry, cyclamen, and kalanchoe, as well as the ever-dependable chrysanthemum and poinsettia. Be sure to give these living plants bright indirect light, keep them cool and out of drafts, and water them just enough to keep the potting mix barely moist. Cacti and succulents are also good choices, but they need direct sunlight and very little water.

The garden is a treasure trove of possibilities for holiday decorations. Pyracantha berries alternated with popcorn make attractive garlands. Oranges, lemons or apples sprinkled with cinnamon or cardamom and stuck with whole cloves are delightfully fragrant pomander balls. Rose hips add bright red and orange colors to green wreaths. Vines from grapes, honeysuckle, wisteria, willow, or ivy will bend into many usable shapes. Eucalyptus pods, pine cones, acorns, and magnolia leaf clusters provide many shades of brown. Bufford's Holly, which grows better here than the traditional variety, gives us stickery-leafed green with red berries. And, of course, the mistletoe.

Herbs, too, can trim yule logs, flavor jelly, give fragrance to clusters of twigs or wreaths and perfume the air in stovetop potpourris.

Don't worry that your houseplants don't seem too perky now--they're going dormant, just like many plants outdoors. Plants need this rest, so stop feeding them, and water them only to keep the soil barely moist. Also, be sure they're not getting blasted with hot air from a heater vent or fireplace. Plants close to windows may get too much cold air at night, so move them or provide a shield between them and the window. The most comfortable temperature range for indoor plants is 65-75 degrees, with extremes of 60 and 80 degrees.