Seasonal Tips
December Tips
By Kathie Carter
Cooperative Extension/ Botany Plant Sciences Department
University California Riverside
December marks the beginning of winter here in southern California. The days grow cooler and shorter, shadows longer, and plant growth comes to a near halt until sometime in February. Normally December fulfills its winter role with cold and rain, although it can sometimes bring a heat wave that makes you thonk that August has returned. So be prepared to protect tender plants from possible frost or, if the weather brings hot drying winds, be prepared to water your plants until they subside.
If you're too busy to give the garden much attention this month, most plants will do quite well with little help. So if you prepared for winter in the fall, sit back and enjoy the holidays. If you still haven't finished your fall gardening tasks, don't worry, the fall planting window hasn't quite closed just yet. You can treat December as part of fall and plant just about anything although most plants would have been happier planted earlier when the weather was warmer and the days were longer. It is still a good time to plant most trees and shrubs, except for palms. Cool-season flowering annuals can also be transplanted into landscape borders or containers.
If you can find the time, working in the garden this month is wonderful. The weather is cool and when it rains and the soil dries a little, it's perfect for digging. However be careful not to go to work too quickly after a rain. Grab a fistful and squeeze it lightly: If it crumbles when you loosen your grip, it's just right; if it stays in a tight ball, it's still too wet.
fter the holidays, if you find yourself with time on your hands or you just can’t wait, you can get a head start on the New Year by tackling some of January's tasks. You can shop for bare root stock (roses, fruit trees, grapes, berries, strawberries, and some vegetables) in the nurseries and plant them early. It's also a good time to plant the winter-blooming camellias. Camellias and azaleas are best planted while in bloom which is helpful because you can see what colors you are adding to your garden. You can keep quite busy planting between any rains we might get this month.
With the seasons quickly changing to winter, day length has become shorter and there is less time to get the needed things done in the landscape. In the urban areas of California we can still have warm spells in which some weed seeds can germinate. Sowing seeds for winter landscapes is still also possible. Just remember that seeds will germinate and plants will grow more slowly in the cooler conditions.
Even in California's urban dead of winter landscape it is nice to have greenery and some flowers to take the mind off of the drab winter months. Protect citrus and avocados from severe cold by wrapping the tree trunks.
Watering before a frost is advisable, but be careful not to waterlog the trees. The waters trees are able to take a bit more of the cold temperature than if they are exposed to dry and cold weather. Some trees are completely dormant now and could use a dormant spray application. The second scheduled spray would be applied in January. The dormant spray should be applied when there are several days above 40 degrees (usually not a problem in urban areas of California).
Ornamental flowers to plant in December include gazania, alyssum, cyclamen, lobelia, nasturtiums, alyssum, cyclamen, lobelia, nasturtiums, pansies, Iceland poppies, azaleas, calendulas, primroses, snapdragons and stocks. Poinsettias are a perfect plant for the season with a multitude of shades, ranging from greenish-white to deep red.
fter the holidays, if you find yourself with time on your hands or you just can’t wait, you can get a head start on the New Year by tackling some of January's tasks. You can shop for bare root stock (roses, fruit trees, grapes, berries, strawberries, and some vegetables) in the nurseries and plant them early. It's also a good time to plant the winter-blooming camellias. Camellias and azaleas are best planted while in bloom which is helpful because you can see what colors you are adding to your garden. You can keep quite busy planting between any rains we might get this month.
With the seasons quickly changing to winter, day length has become shorter and there is less time to get the needed things done in the landscape. In the urban areas of California we can still have warm spells in which some weed seeds can germinate. Sowing seeds for winter landscapes is still also possible. Just remember that seeds will germinate and plants will grow more slowly in the cooler conditions.
Even in California's urban dead of winter landscape it is nice to have greenery and some flowers to take the mind off of the drab winter months. Protect citrus and avocados from severe cold by wrapping the tree trunks.
Watering before a frost is advisable, but be careful not to waterlog the trees. The waters trees are able to take a bit more of the cold temperature than if they are exposed to dry and cold weather. Some trees are completely dormant now and could use a dormant spray application. The second scheduled spray would be applied in January. The dormant spray should be applied when there are several days above 40 degrees (usually not a problem in urban areas of California).
Ornamental flowers to plant in December include gazania, alyssum, cyclamen, lobelia, nasturtiums, alyssum, cyclamen, lobelia, nasturtiums, pansies, Iceland poppies, azaleas, calendulas, primroses, snapdragons and stocks. Poinsettias are a perfect plant for the season with a multitude of shades, ranging from greenish-white to deep red.
Cool-Season Flowers. If you live in a mild transitional zone (non-mountainous areas of Southern California), there is no need to wait for spring; you can still fill in those bare spots with cool-season flowers.
Spring-Flowering Bulbs. Finish planting any spring-flowering bulb that doesn't require pre-chilling. The rule of thumb is to plant the bulbs before December 25. When planted later, the flowers will be fewer and smaller. Tulips, crocus and hyacinths should be refrigerated for 6 to 8 weeks before planting. They need cold earth so start planting between Christmas and New Year's Day unless there's a heat wave. If this occurs, wait until January but plant before January 10th.
Grapes. Prune from December through early January. See the University of California Cooperative Extension California Master Gardener Handbook or the Sunset Pruning Handbook methods of pruning grapes. Save the trimmings to make ornamental wreaths and baskets.
Fall-bearing Raspberries. Cut back fall -bearing raspberries after they become dormant. 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.
Native Plants. This begins the growing season for California Natives so if the weather is dry, water these plants. Many native plants can also be pruned now. Some people do not prune natives at all but the shape of some plants can be improved by judicious pruning.
Peaches. If your peach or nectarine had leaf curl (puckered, yellow and red leaves) this year, spray it with a fixed copper material at full leaf fall. If you sprayed your peach trees in November, wait till January for the second treatment.
Deciduous Fruit Trees. Dormant oil spray deciduous fruit trees. Dormant sprays are applied after a deciduous plant has gone dormant and dropped its leaves. Dormant sprays are used to control over wintering mites and insects such as scale and mites. Other sprays are used to control certain fungal diseases such as peach leave curl. You can also prune deciduous fruit trees this month or wait until January. Be certain the leaves have dropped before pruning.
Peaches. If your peach or nectarine had leaf curl (puckered, yellow and red leaves) this year, spray it with a fixed copper material at full leaf fall. If you sprayed your peach trees in November, wait till January for the second treatment.
Deciduous Fruit Trees. Dormant oil spray deciduous fruit trees. Dormant sprays are applied after a deciduous plant has gone dormant and dropped its leaves. Dormant sprays are used to control over wintering mites and insects such as scale and mites. Other sprays are used to control certain fungal diseases such as peach leave curl. You can also prune deciduous fruit trees this month or wait until January. Be certain the leaves have dropped before pruning.
Revised December 1, 2008