December Garden Tips

Professor Hooticulture garden tip owlWelcome to Garden View’s monthly gardening tips. We hope you find this information useful and check back often as we will feature new tips each month as well as new articles to the right.

Professor Hooticulture garden tip owlWelcome to Garden View’s monthly gardening tips. We hope you find this information useful and check back often as we will feature new tips each month as well as new articles below.

Prune Berried Plants

Cut holiday decorations carefully so you thin out and improve the shape of donor plants. Sprigs of needle-leafed evergreens, holly pyracantha (left), and toyon are attractive choices for arrangements.

Prune Evergreens

Many evergreen trees and shrubs benefit from a light winter grooming. Prune to shape cedar, cotoneaster, fir, juniper, magnolia, pine, pittosporum, podocarpus (right), pyracantha, and viburnum.

Prune Natives

Cut California Fuchsia Zauschneria californica (left), Coast sunflower (Encelia californica), Matilija poppy, and needle grass (Nassella) nearly to the ground. Prune Cleveland sage, coyote mint (Monardella villosa), and Island bush snap-dragon (Galvezia speciosa) more lightly: about one-third.

Water Natives

This is the growing season for California Natives like the Matilija poppy (right) so if the weather is dry water these plants.

Care for Gift Plants

Azaleas, cyclamen (left), and poinsettia would actually prefer to be outdoors; while they’re in your house, display them in as cool but bright a spot as possible-away from heaters and the fireplace. If pots are trimmed in decorative foil, punch a hole though the wrap or remove it so plants can drain well. Keep soil slightly damp, never soggy. Though Poinsettias prefer to grow outside the gift poinsettias we purchase in December for holiday color are actually grown in greenhouses under perfect conditions and forced to bloom and produce red leaves in December rather than their natural growth pattern in spring. When placed out doors they are usually very delicate and not acclimated for severe weather conditions. Changes in temperature, over or under water, rain and the cold may lead to their early demise or severely damage the red leaves.

Carrotwood Trees

Carrotwood trees (Cupaniopsis anacardioides) are blooming now, if yours is the fruiting type you can eliminate or minimize the fruit by spraying Florel® brand Growth Regulator. It is registered to reduce or eliminate undesirable fruit development on many ornamental trees and shrubs Application must be made prior to fruit set; apply at the mid to full-bloom stage in sufficient water to wet (do not spray to run off). Good spray coverage is essential for complete fruit elimination.

Clean out Rain Gutters Now

Falling leaves can plug the gutters and drains causing leaks in the roof and damaging interior walls.

Turn off Water on Deciduous Fruit Trees and Roses

Many of us can turn off automatic sprinklers for fruit trees, roses and many landscape beds. Most plants need very little extra water in winter. Remember to irrigate occasionally if we If we have warm spell or Santa Ana winds.

Plant for Spring Color

Best bets are Begonia Semperflorens, calendula, candytuft, Canterbury bells, carnation, cineraria, columbine, delphinium, dianthus, dusty miller, English daisy, foxglove, Iceland poppy, lobelia, pansy, phlox, English primrose, Primula malacoides, ranunculus, Shasta daisy, snapdragon, stock, sweet alyssum and viola (left). If you need dabs of quick color, these will be available in 4-inch post; calendula, candytuft, cyclamen, pansy, Iceland poppy, English primrose, and snapdragon.


Prune Grapes from December through early January. See the Sunset Pruning Handbook for the three major methods of pruning grapes. Save the trimmings to make ornamental wreaths and baskets.


Cut back raspberries. Low-chill raspberries bear fruit over a long period on new wood. Rejuvenate plants this month (or in January) by cutting back to the ground all canes that have fruited.


Harvest Fuerte avocados from now through March by cutting stems close to the fruit, not breaking them off. It’s ready when picked fruits soften without shriveling, so try a few first to see how they do. Taste-test to make sure they are ready.


Start treatments on colored hydrangeas over three years old to control or change flower color. Blue hydrangeas grow on plants in containers with acid soil mix, maintained by periodically applying a solution of 1/2 oz. aluminum sulfate (non ammonium sulfate) per gallon of water to already dampened soil-now and throughout the year. Hydrangeas turn pink in less acidic soils or by applying superphosphate heavily (compared to package instructions) now and in late winter. Treatments must start now in order to make a difference.

Plant Trees and Shrubs

This is an excellent time to plant any tree or shrub that isn’t frost-tender or sold bare-root in January and February. Plants put in now should establish themselves before cold weather arrives.

Plant Bare-Root Stock

Deciduous fruit and shade trees, cane berries, and roses arrive at nurseries this month. Shop early to get choice plants; if you are unable to plant immediately, heel bare roots into damp soil, sawdust, wood shavings, or sand.

Plant Vegetables

For spring harvest, plant the following from pony packs now; broccoli, Brussels sprouts, cabbage, cauliflower, lettuce, Swiss chard. Sow seeds of all of these and also beets, carrots, celery, kale, kohlrabi, onions, parsley, peas, radishes, spinach, and turnips.

Plant Bulbs

Shop for bulbs in nurseries now, choosing the largest, firmest ones you can find, then set them out.

Prepare for Frost

In those areas where frosts are just an occasional thing keep plantings well-watered so whenever a freeze threatens plants are more likely to survive. A “turgid” well-hydrated plant is better-equipped to recover than a dehydrated plant. If a plant is damaged by frost resist the urge to prune the damaged parts. They may well protect the rest of the plant during any subsequent frost.

Feed Shrubs and Trees

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

Spray Deciduous Plants

Rake up and dispose of all leaves and debris under deciduous fruit trees. Spray with dormant oil which is usually a combination insecticide-fungicide such as oil mixed with lime sulfur of fixed copper to control scale insects overwintering mite and insect eggs and fungi (including peach leaf curl). With your sprayer, drench all parts of plants and the soil beneath them.

Mow Lawns

Not a top priority this month, mowing is necessary nevertheless. With mower blades set about 1½ -inches high, cut grass about twice a month or more often if it needs it.