For The Answer
By Calvin R. Finch, PhD, Conservation Director,
San Antonio Water System, and Horticulturis
December Gardening Calendar
November was generally mild, but it got cold enough at the end of the month that bougainvillea, mandevillea, hibiscus, poinciana, esperanza, firebush, and other tropical and subtropical plants quit blooming.
It is probably time to consider shelter for the potted plants. Bougainvillea and mandevillea need to be protected from freezing temperatures but do not need light or watering over the winter. Hibiscus, however, does not go completely dormant so winters best in a greenhouse or sunroom where they are protected from cold and can receive some light. Water them occasionally. If you love Satsuma oranges, Meyer lemon or other citrus, it can go in the greenhouse or be left out as long as you are prepared to cover them when freezing temperatures are forecast.
If temperatures are going to reach less than 26 degrees F put a heat source (Christmas lights, mechanics light, etc.) under the blanket and plastic tent.
Firebush, poinciana, and esperanza are all root-hardy plants. They may freeze back but will resprout in late spring
In the vegetable garden, the broccoli, spinach, and other greens are welcoming the cooler weather. They do not need any protection from freezes. The broccoli variety, Marathon, that most of us had to purchase as transplants this year, is very slow to head. The foliage looks good but be patient on the heads. Harvest collards, leaf lettuce, mustard, spinach, and other greens one leaf at a time, as you need it for the dinner table. If you never remove more than one-third of the foliage, the plants will yield greens until late spring. Fertilize greens every three or four weeks with lawn fertilizer, 1 cup per 10 foot of row.
The English peas prospered in November, if you got them in the ground in October, they should be blooming now.
Harvest tomatoes as they show any color. They will turn red within one day in the kitchen and there is less chance you will share with the birds (and squirrels) or lose everything in an unexpected freeze.
Use the leaves that have fallen from your oaks, mulberries, pecans, cedar elms, and mesquite. The easiest way to use them is to mow them where they lay on the lawn. The remains decompose quickly and provide nutrients and organic material for the grass. Leaves also make great mulch. Use them 4 or 5 inches deep over the roots of newly planted trees and shrubs. If you put the leaves in the compost pile, add some lawn fertilizer to speed up the breakdown to compost.
If you feed the birds, it is time to fill the feeders. Use thistle seed for American and lesser goldfinches. Cardinals, titmice and chicadees love sunflower seed. Suet is good for the insect-eating birds like woodpeckers. The pepper-flavored suet will be eaten by the birds but passed up by the squirrels. It is also best to invest in a steel feeder with a weight-sensitive perch for the sunflower seed. They baffle the squirrels and even will shutout the white wing doves. If you want to feed the doves put out a small amount of serrated grain or a cheap mix of birdseed every morning on the ground or a low tray. It may also attract some of the American sparrows. If you only put out as much as they eat by noon, the seed will not attract rodents.
December is still a good month to plant trees and shrubs. It is also a good month for bargains. Buy your gardeners a gift certificate at their favorite nursery. If you are considering a live Christmas tree select an Aleppo pine, Italian stone or Japanese black pine. They all will survive well in our climate when planted after the decorations are removed. The Afghan or Eldarica pine makes a fast-growing alkaline-tolerant pine for rocky, well-drained sites, but they do not last long in heavy clay or low spots. They become infected with a fungus that kills them from the bottom up. The acid-loving pines (loblolly and others) and spruces will die within a few years in our soil and heat.