December to-do list for gardeners

By Rebecca Jepsen
For the Mercury News
December 4, 2009

Gardeners and homeowners, here's your December to-do list:

Clean garden beds in preparation for winter. Many insects and diseases overwinter in fallen debris. Prune diseased leaves from roses, camellias, rhododendrons and azaleas. Leave leaf litter under oaks, pine and junipers; the leaf duff helps protect the roots.

Watering is important if there has been no rain for a week or two. Use a moisture meter or a shovel to dig into the soil (at least six inches below the surface) to see if the soil has dried out. This is especially important for recently installed plants and trees.

Mistletoe is a parasitic plant that reduces the vigor and health of its host tree. Cut off any affected limb 18 inches or more below the mistletoe attachment. If this isn't possible, remove the mistletoe and wrap the infected area with black plastic to prevent re-sprouting.

Prune apple trees that have weak or unproductive branches. Apple trees produce fruit terminally on spurs located on wood that is 2 to 8 years old. Pruning allows sunlight into the tree to encourage good spur development.

Prune blackberries as soon as harvest is complete. Remove all wood that has produced the current year's crop, and trellis remaining large branches immediately; a fan shape is recommended. Tipping (removing the end of the canes) will promote larger berries and help keep the plant more manageable.

Harvest kiwis when they are still hard, then soften at room temperature. Watch the vines for signs of ripeness; a few fruit will turn soft and the skin color will change from greenish to full brown. Fruit can be left on the vine after the leaves fall off. Kiwis can be stored in the refrigerator for up to four months or at room temperature for about two weeks.

More tips: www.mastergardeners.org/tips/december.html.

WHAT TO PLANT NOW

Transplants: asparagus, horseradish, lettuce, garlic, onions, peas, rhubarb. Local nurseries should have a good supply of most of these.

Seeds: potatoes, radishes, bell beans.

For a list of cool-season vegetables that do well in Santa Clara County, check out www.mastergardeners.org.