San Marcos — Gardening in December is a pleasure. Gone are the hot, hot and humid days of summer when everything, including the gardener languishes in the heat. In these delightful days of cool nights and pleasant, albeit sometimes warm days, plants thrive and visiting butterflies flit from one to the other in complete abandon. This is the season Texans love. It is a time to enjoy. It can also be a time to work. December is an active planting and seeding season.

December weather can fluctuate from day to day as each cold front arrives straight out of the west or the north. This year they seem to arrive on schedule, but without the accompanying moisture. Evergreen plants can be damaged by a cold, dry freeze, much more than a cold wet one. The high winds and low humidity dries the leaves leaving them susceptible to freezer burn. If it looks like there will be no rain with an incoming cold front predicted to drop temperatures to freezing, water all plants thoroughly. In fact, during a dry winter do water at least once a week.

When extreme temperatures are expected, cover all marginal evergreen plants with a frost blanket, a thin, lightweight white fabric that allows some air and sunlight in while keeping the cold and wind out. It is available at most garden and hardware stores. Do not use plastic as it can burn plants. Or if you have one prized pot plant that is just too big to move, throw a heating blanket over it. I have a Florida Key Lime tree that has its very own baby blue blanket for freezing nights, keeping it nice and toasty.

The up side of the current dry weather patterns is you can till your garden in preparation for spring planting. Turning under dry vegetation will allow earlier planting in the spring and immensely help drainage in clay soils. You can also put shredded leaves directly in the garden and turn them in. Now is the time to add compost to the garden, prepping it for spring. If you add organic material to the garden now, it will have time to decompose, adding valuable nutrients to the soil in time for spring planting. If you have a sloped area to your garden you may opt for a cover crop like alfalfa, barley, or rye to protect the area from soil erosion.

But some areas of the garden are still producing. Kale, spinach, bunching onions, parsnips, and carrots will survive all winter long in the garden so now is the time to prepare them for cold weather, too. Top-dress these plants with compost or manure and mulch, which will reduce the damage done from freezing and thawing. Now is the time to weed around strawberry plants and transplant runners, taking care to dig plenty of soil with the roots.

After caring for perennial garden plants and harvesting tender crops, pull up all stakes and trellises except those that are marking over wintering plants. Clean them of all plant material and soil. Hose them down on a sunny day and let air dry. Check each trellis for damage and repair. Tie them in bundles and stack, preferably in an upright position, in a sheltered location.

If you want to extend the growing season, construct a cold frame, also known as a sun box. These are very simple structures that provide a favorable environment for growing plants into, and in mild winters, through the cold months. They require no outside energy, relying on the sun for their source of heat and can be constructed of plastic, glass or fiberglass and wood. The ideal location for one will have a wall or plant structure for protection against cold north winds and a southern or southeastern exposure for sun. Sink the frame into the ground for insulation. The top can be hinged and slanted to the front to drain off rain. Old glass windows hinged to one large frame makes a great cold frame. They are invaluable in early spring, providing a transitional nursery for tender seedlings to outdoor weather and are easy to build.

Some perennial plants like Beebalm, Lion's Tail, Mexican Marigold, Lemon Grass, Lemon Verbena and Pineapple Sage need a light freeze to turn their tops brown, indicating that it is time to cut them back just above the base of the plant and mulch. By now you should see some new growth coming up from the base, getting ready for next year. Lavender, rosemary, sage and thyme should be lightly mulched. And if it ever rains again, make sure the plants have good drainage by seeing the mulch is not piled up around them. Echinacea, germander, mint, and oregano can also be trimmed back to their rosette. Now is the time when chamomile, parsley, rue, santolina, Winter Savory, sorrel, and thyme rule in the herb garden. They thrive in cooler weather.

January and February weather can sometimes be brutal and icy. December is a very good month to spread some mulch or build a walkway. It is easier to spread gravel or decomposed granite in 70-degree weather than in 90-degree weather. Had grass die on you this summer? Pull up the few sprigs that are left and sow winter rye. Or plan ahead for spring. Clear and rake, then sow a handful or two of wildflower seeds. Yes, it is a tad late, but not past the deadline. The weather is still warm enough for good germination, provided you water if no rain is forthcoming. Just picture a bed of wildflowers visited by wildlife of bees, birds and butterflies come springtime.

If you do decide the over seed bare spots of lawn with winter rye, keep it mowed low and watered. It will slow down the growth of warm weather grasses and wicks moisture away from the viable roots of permanent summer turf.

Roses, trees, grape vines, ornamental and fruit-bearing trees and shrubs can be set out this month. Evergreen plants can also be transplanted. Once they are planted, water them thoroughly and mulch well around them.

Tulips that have been refrigerated can be planted now or stored in a refrigerator until you have time to plant them.

Dormant spraying for scale insects and other pests and diseases can be applied during the daytime, unless there is a danger of freezing temperature the following night. And speaking of freezing temps, once fruit or ornamental trees lose their leaves you can get a jump on pruning. Just take care NOT to prune spring flowering plants unless you are willing to forgo spring bloom for next year.

Watch for the Halcyon Days in December; two weeks of calm weather often followed by blustery winds. Ancient Greeks and Romans believed these occur around the time of the winter solstice, which begins on December 21 this year at 7:04 a.m. according to the Farmer's Almanac. The kingfisher or halcyon bird is said to have charmed the wind and waves of the sea soothe waters were especially calm during brooding season. Two weeks of calm weather sounds pretty good, plenty of time to enjoy your garden.