December can be one of the coldest months of the year in Tulare and Kings counties, and the winter solstice occurs on Wednesday, December 21 at 1:48 p.m. This is the moment when the Sun reaches the Tropic of Capricorn, which cuts the equatorial line through South America, the tip of Africa and through Australia. At noon, the sun rises to its lowest point of the year before dipping below the western horizon, and therefore the day is both the shortest and the coldest. It’s also the first day of winter and from then on the days get longer again. About a week before and after the solstice, in the middle of the day, the sun doesn’t seem to rise very much, seems to “stand still” and that means solstice: sun stands still. Solstice celebrations are most often marked with greenery for the promise of a returning spring, Christmas logs and candles to increase the light for the day, and anything nature related in general to remind us of this , that we live on a living, changing, complicated planet a vast universe. What better companion for contemplating those deep thoughts than using our muscles and energy for a few conservatory tasks?
PLANTING: Bare root planting begins in December for roses, berries, and deciduous trees. Frost-sensitive plants should only be planted in spring. Even with frost-hardy species, use a layer of mulch to protect plant crowns and roots from freezing. Finish planting flower bulbs and wildflower seeds. In the edible garden, in addition to perennial herbs, you can still transplant seedlings of most cool-season vegetables. Also plant onions, asparagus and rhubarb. The last two are perennials, so you won’t be harvesting them until well into next year. You can also plant lettuce and related green lettuce seeds in cold frames.
MAINTENANCE: Pay attention to frost warnings and protect your sensitive plants. Plants survive better when kept moist but not overwatered. Remove old fruit, called “mummies,” left on fruit trees. Water citrus trees well this month if the rain is not constant to have a good harvest next year. Also, water your other trees deeply during a dry spell that lasts longer than two weeks, even when the trees are dormant.
You can start pruning your winter deciduous trees, shrubs and fruit trees or wait until January, especially if the plants are not fully dormant and safety is not an issue. Do not prune if frost is expected within the week. Force your roses into dormancy by removing leaves that have not fallen off. Mow cool-weather lawns that should be actively growing by now to three inches. This also applies to overgrown lawns.
If you’ve had major aphid, mite, scale, or whitefly problems on your fruit trees or roses, spray dormant horticultural oil after the leaves fall to kill overwintering adults. Hand-pick slugs and snails or bait iron phosphate. Iron phosphate needs to be replaced after a rain, but it’s not toxic to humans, pets, or beneficial insects, nor does it appear to harm soil microorganisms. In late December, spray early flowering peach and nectarine trees with copper fungicide to control peach leaf curling if you’ve had symptoms this year.
Do you see any white moths around your winter vegetables? The moth looks for good spots to lay its eggs, which hatch into the cabbage shears and eat holes in the leaves, sometimes decimating the crop. There’s not much you can do about the moth, but seeing the moth is a signal to search under the leaves for the next few days to catch the small, green caterpillars before they do much damage. Large plants can survive some damage, but seedlings can be devoured. Chemical control is BT (Bacillus Thuringieis) or go chemical free and hand pick and toss caterpillars somewhere hungry birds will find them.
Finally, keep up with the cool season weeds so it doesn’t become a chore and overwhelming later on. Conventional household white vinegar or commercially formulated non-systemic organic herbicide can be kept in a labeled spray bottle in the garden for weed zapping on sunny days. Or chop them out easily. You can also try adding more mulch and shading them, which works well on those low sun days. Use layers of cardboard or newspaper as a decomposing mulch. You can cover the paper products with wood or leaf mulch, or with hay or straw in a practice called “leaf mulching.”
PRESERVE: Keep in mind that many caterpillars, especially on ornamental plants, do little damage and turn into desirable moths and butterflies. All butterflies are food for birds, lizards, toads, and other creatures in the food chain. Use common sense and a little damage tolerance to encourage a healthy garden full of interesting life, even in urban neighborhoods.
Leave a bunch of branches from trees and shrubs for birds to hide in if they can. And don’t forget the water. Small streams as part of a water garden design, Mister style sprinklers or a fresh water bird bath are popular with our wild bird friends. When preparing to prune trees, inspect the high branches of large trees for bird nests and avoid pruning when hawks or other birds are nesting.
If you haven’t already, prune the blooms on tropical and other non-native, orange-flowered spurge varieties. Those monarchs who stay here for a ready source of food will not survive the cold winter; they have to migrate. Consider replacing your non-native milkweed with a California native variety now that they are readily available at nurseries. Once you’ve established your spurge, think beyond a single species to expand habitat benefits.
Cover the bare ground with plants, mulch, or erosion control fabric to reduce the loss of more topsoil. If you have significant stormwater runoff, consider installing a creek, rainwater basin, swale, or French drainage system.
I wish you wonderful winter holidays full of useful garden companions and delicious surprises.