December Garden Tips
by Thea Fiskin, UC Master Gardener

December days are colder, shorter and shadows are longer, so plant growth slows way down. Most plants need little care this month, so if you get too busy with the holidays, don't worry about the garden. If you find you need a break from all the festivities, then maybe a walk outside to pull a weed or two is just the answer. I enjoy going out and counting the daffodils.

PLANT DISEASES
If camellia blossoms turn brown and rot, then camellia petal blight is the likely cause. Splashing water disperses the fungal spores from the rotten petals to new flowers. To control it, pick infected flowers and throw them away. Also throw away any fallen flowers or leaves (we call this sanitation) to prevent water splashing on them. This limits the amount of inoculum near your plants and minimizes the spread of the disease.

If peach or nectarine trees had curled or puckered leaves this summer, then take preventative measures against the fungal disease called "peach leaf curl" for next spring. Rake leaves when they fall, remove any fruit mummies, and discard both rather than put them in the compost pile. Spray trunk, branches and ground underneath tree with a copper-based fungicide or a Bordeaux mixture (slurry made of hydrated lime and copper sulfate) or a synthetic fungicide. Be aware that products must have at least 50 percent copper to be effective; those containing less do not adequately control leaf curl - despite advertising claims.

GARDEN CHORES
Continue to heed frost warnings and protect sensitive plants. Plants will survive better if well watered, so don't let them dry out.

Prune deciduous trees after they lose their leaves, except for the spring flowering varieties such as forsythia. Prune these after they bloom. Consult pruning books or Sunset's Western Garden Book, if you are uncertain how to proceed. Use the prunings of fir, holly, juniper, pine, pittosporum, magnolia, and redwood for holiday decorations. Prune grapevines and use the cuttings for wreaths.

Prune raspberries by cutting to the ground the canes that had fruit this year.

Remove winter weeds popping up now. Each weed plant has thousands of seeds so getting them early will save you a lot of work later on. In large flowerbeds or lawns apply a preemergence herbicide to prevent annual weed germination. Discourage weeds by mulching flowerbeds, shrubs and trees with a thick layer of organic (shredded or chipped bark, etc.) or inorganic (gravel or rocks) mulch. If using preemergence herbicides, spray first then add a layer of mulch.

CRITTER CONTROL
Spray fruit trees, nut trees, and roses with a dormant oil spray to kill any overwintering aphids, mites, scale etc. Hand pick slugs and snails or set out bait. Control by eliminating their hiding areas.

WHAT TO PLANT
For winter color buy six packs of calendulas, Iceland poppies, pansies, primroses, sweet peas, snapdragons, stock, and violas. It's not too late to plant and they will continue to bloom till the hot weather returns in April or May.

It's nearing the end of the bulb planting season, so nurseries should have them on sale. The selection may be limited, but the prices should be right. Remember hyacinth and tulip bulbs need to be chilled for six to eight weeks in the refrigerator prior to planting, so you may want to opt for other types.

Later this month bare root trees and roses will arrive in nurseries. Shop early for the best selection. If you are looking for a particular variety, you might want to call ahead to request it.

Houseplants - Houseplants will need humidity now that heaters are on. Spritz them with water or better yet set them on a humidity tray. Line a tray under the plant with pebbles and add water to just below the surface of the rocks. Never let the plans sit directly in the water. Some houseplants are particularly cold sensitive, so move plants away from doors where they will get cold drafts. Wipe off foliage to allow leaves to breathe easier and absorb more light. Snip off yellow or dead leaves.

Is there a gardener or new home owner on your list? Gardeners love to receive garden books, plants, tools, or unique garden art for their yards. Garden books are great gifts, especially for the novice gardener; try to look for books geared to our area, rather than ones written for the East coast.

Happy Holidays from all the Master Gardeners.

December 4, 2003