December in the Contra Costa Garden

December Garden To Dos

General Garden Care

• Turn off irrigation systems if raining—if not raining, reduce time and frequency to the minimum amount of time needed to keep plants alive.
• Remove summer-created watering basins to prevent standing water around trees and shrubs from causing root or crown rot.
• Protect tender plants if frosts are predicted: use outdoor lights or build a light weight frame and cover.  Antitranspirants such as ‘Cloudcover’ will provide a bit of protection.  http://www.ipm.ucdavis.edu/PMG/GARDEN/ENVIRON/frostdamage.html
• Avoid compacting wet soil:  minimize walking or driving and don’t work wet soil.
• Avoid walking on frosted grass; the cells rupture and turn brown.
• Clean up all garden beds; compost spent garden plants.
• Turn compost; cover if raining.
• Use rainy days to clean, sharpen and lubricate garden tools; —store in dry area.
• Check plants under eaves—are they getting enough water?
• Order seeds (this month or next).
• Inventory all pesticides and take unneeded and outdated chemicals to the household hazardous waste center; consider using IPM methods rather than replacing chemicals.  http://www.ipm.ucdavis.edu/index.html.

Fruits & Vegetables

• Pile dead leaves into a trench in unused vegetable beds, and cover with soil. By next spring, the leaves will be composted and the beds ready for planting.
• Control peach twig borer, San Jose scale, mites or aphids on apricots with a dormant oil spray. Dormant oil sprays can be applied to dormant ornamentals as well as fruit trees.  http://www.ipm.ucdavis.edu/TOOLS/PNAI/pnaishow.php?id=39
• Remove “mummies” and fallen fruit to minimize spreading diseases next spring.
• Prune Feijoa sellowiana shrubs after fruit is harvested.

Flowers & Landscaping

• Prune winter-flowering shrubs just after bloom.
• Prune hardy deciduous and evergreen trees.
• Prune evergreens for holiday decorations.
• Water living Christmas trees.
• Plant ornamental trees and shrubs EXCEPT Subtropicals.
• Plant frost-tolerant perennials such as Ajuga, English ivy (Hedera), heuchera, hosta, lamium, lysimachia, ornamental sages, and Tiarella; frost-tolerant annuals such as calendulas, cinerarias, cyclamen, pansies, English primroses, fairy primroses, Primula obconica, and snapdragons.
• Select blooming azaleas and Camellia sasanqua varieties, foliage plants: dusty miller, ferns, liriope, or dwarf Nandina domestica.
• Pre-chill tulips and hyacinths for forcing indoors.
• Mulch bulb beds to protect from freezing and to conserve moisture if winter is dry.
• Check all hardy bulbs potted earlier; move indoors into good light when roots develop and 2 to 3 inches of new growth is visible.