Although many of us don't make it out into our gardens much this time of year, there is plenty to do. For a splendiferous Spring and Summer display, a bit of work now is well worth the effort. Or better yet, call us, and we'll do the fine gardening work for you!
_ When hard freezes are expected, protect tender plants from potential frost by tenting with burlap, a blanket, or Easy Gardener’s Plant and Seed Blanket. Be sure to keep the cover off of the foliage to minimize damage to branch tips and flowers. Cloudcover, a polymer that prevents desiccation during frost, protects plants to about 28°F. Pull potted plants under the eves of the house and if you expect a big freeze run an extension cord out into your citrus and put a 60 or 70 watt bulb under the cover. Be sure to remove the covers first thing in the morning as temperatures rise.
_ If you haven’t done so already, move your containerized tender and tropical plants close to the house during the cold months.
_ Apply dormant spray to deciduous trees and shrubs if aphids, scale or whiteflies have been a problem in previous seasons.
_ Apply tri-basic copper sulfate or lime sulfur for peach leaf curl now into mid- February.
_ As camellias begin blooming, you may notice brown splotching on petal margins of open flowers, partly open flowers and flower buds. These are characteristic symptoms of camellia petal blight, a fungus for which there is no cure. Sanitation is the key to reducing symptoms: Remove infected flowers and buds and try to not let infected petals hit the ground. If they do, gather and place them in the trash immediately - do not compost!
_ Azaela flower blight has similar symptoms as camellia petal blight, but it can be controlled with a fungicide applied before the buds begin to show color. Use Rose Pride (Fuginex) or Garden Disease Control (Daconil).
_ Harvest citrus. 'Eureka' lemon, mandarins, 'Washington' navel orange, and several other citrus trees are producing now, so pick while fruit is ripe. If you have more than you can use, we at Botany gladly collect surplus harvest and distribute it to families who will make good use of it or donate the excess to a food bank (for a list, visit cafoodbanks.org). You can also contact the non-profit Village Harvest (888/378-4841) to send a team of trained and equipped volunteers to harvest and donate the fruit for you.
_ Pick up fallen fruit, remove dried fruit on trees (“mummies”), and rake leaves, placing all debris in the trash. Do not compost! Fruits and leaves may harbor overwintering insect pests and fungi. Removing both decreases the incidence and proliferation of pests and diseases the next growing season.
_ To keep fruit and shade trees, grapes, and berries shapely, prune them while they're dormant. It is advisable to use pruning shears to make cuts up to ¾ inch in diameter, loppers for cuts ¾ to 1 inch in diameter, and a pruning saw for branches more than 1 inch in diameter.
_ Prune evergreen perennials such as Penstemon, Chrysanthemums, lavender and Salvias now, if you haven’t already. If they’re still in color, you can wait to cut back absolutely no later than Valentine’s Day. Pruning your evergreens keeps them compact and dense. New growth makes the plant appear fresher. DO NOT prune lavender all the way back into wood with no leaves. It will not recover.
_ Ornamental grasses should have been cut back by now. Some gardeners appreciate the ornamental effect of the dried seed heads through the winter months and those can be cut back as late as Valentine's Day but no later.
_ Time to prune garden hydrangeas (Hydrangea macrophylla). This species blooms on new growth from one-year old wood -- aim your pruning cuts just above the largest pair of buds on this wood. Hydrangea bushes often need to be thinned out by removing some of the old gnarly stems right to the ground. Each year one-quarter to one-third of the stems should be removed to permit new ones to grow. All stems pencil size or smaller should be removed. If powdery mildew has been a problem during the summer months, spray them with Microcop or Liqui-Cop after pruning as a preventative; and during the summer spray with sulfur if mildew appears.
_ Wisteria should be pruned before it blooms; cut the new whippy, vegetative growth back to within two buds from the main stem. Be sure to leave the fat, elongated buds that will produce flowers.
_ Roses should also be pruned now. If you wait until later the plants have often started to sprout out lots of new growth. The main purpose of this pruning is to clear away diseased material. Dead leaves should also be picked up and the ground covered with a fresh dose of mulch to seal in the fungal spores. As much of the introduction of the disease organisms to the plants comes from splashing raindrops, cleanliness matters for the more disease prone roses. Try to refrain from any pesticide or fungicide spraying unless the bugs are just too thick for the plants to survive.
_ Look for broken and torn branches on trees after storms. Prune to healthy tissue, using heading cuts if parts of branches have broken or torn and removing entire branches if needed. Consulting a simple, informative book such as Ortho’s All About Pruning will help you determine where to prune and how to make the proper cut. If severe damage is done to older, mature trees, we strongly encourage you to seek the services of a certified arborist. While you may pay more for their work than you would for a non-certified pruner or gardener, you can be assured that the health and longevity of your trees will not be compromised by poor practices such as topping and incorrect pruning cuts.
_ To intensify the blue or pink coloration of garden hydrangeas, apply aluminum sulphate (for blue) or Oyster shell lime (for pink) in December, January, February, and March. Use oyster shell lime, which contains calcium carbonate, an excellent addition to our soils. Dolomite lime, on the other hand, contains magnesium, of which we already have plenty in our native soils.
_ Consider planting cover crops in unused garden spaces. Cover crops keep soil from compacting during winter rains and add much needed nitrogen to the soil when turned into beds in the spring. Popular cover crops include fava beans, which are also edible, and strawberry or red clover. Winter Cover Crop Mix, available at garden centers, which includes bell beans, magnus peas and purple vetch is another good selection. You can also plant dwarf snap peas from cell packs about nine inches apart. The peas can be harvested and eaten and still provide all the soil benefits listed.
_ To find out how to compost in Santa Clara County contact the Master Gardeners of SantaClara County at (408) 282-3105 or online at http://www.mastergardeners.org/scc.html.
_ Clean and service lawnmowers.
_ Consider watering indoor plants with 2 tablespoons of vinegar per 1 gallon of water once a month to reduce salt-build-up and to lower pH.
_ Tune up your house plants a couple of times a year. Wash dust and dirt off the leaves, check for bugs and flush the soil by running one or two quarts of water through the soil.