Note: An earlier version of this column provided an incorrect phone number for the University of California Cooperative Extension to schedule a Master Gardener speaker. The correct number is 559-241-7515.
The central San Joaquin Valley has received just one quarter of the average annual rainfall to date for the season. We can’t predict with certainty that the coming year will be another drought year, but we should be prepared. If rainfall amounts for the entire season are less than average (11.6 inches), water conservation will once again be an absolute necessity. We must also take steps now to maintain the health of our mature landscape trees which were not able to fully recover from four years of severe drought during last year’s wet winter.
Up to 70 percent of the average household’s water use in the Fresno/Clovis region is used outdoors. In winter, cool-season grass lawns such as fescue need just 8 minutes of irrigation per week and warm season grasses including bermuda need only 6 minutes of watering per week. In fact, both types of grasses are dormant in winter and can do without any supplemental irrigation if the soil is still moist from previous rainfall. Get accustomed to regularly checking soil moisture levels in your landscape and irrigate only when the top inch or two of soil is dry.
The roots of the drought-tolerant plants installed a couple of years ago should be mature enough now to survive on very little water. If you haven’t yet created irrigation zones where plants are grouped together by their water needs, transplant in late January or early February. If rainfall amounts still fall short of average by late spring, put off planting even drought-tolerant varieties.
The effects of the severe drought years on large landscape trees are still very obvious. Twig and branch dieback, pest insect problems (especially borers), and susceptibility to disease are prevalent on drought-stressed trees, even though their roots were soaked by last year’s abundant rain.
Deep-irrigate mature trees monthly during the winter by allowing water to slowly soak the soil at the edge of the canopy for at least three to four hours or until the soil is moist at a depth of one foot.
Winter is pruning season, but giving trees a hard pruning or, as is more common in our area, overpruning or topping the trees, will create a strong flush of new growth that will draw up a lot more water. Poor pruning also further stresses an already stressed tree. During drought years, it’s best to prune lightly, removing only dead or diseased wood and using “heading” cuts on branch tips to control size and growth direction.
Hear from a gardening expert
Fresno County Master Gardeners are available at no charge to speak to your garden groups, neighborhood and homeowners associations, monthly club meetings and professional organizations.
Master Gardeners are volunteers trained by the University of California Cooperative Extension to educate the public on home gardening. They are qualified to speak on a wide variety of gardening topics and answer all your gardening questions. Call 559-241-7515 for information on scheduling a Master Gardener speaker.
Send Elinor Teague plant questions at firstname.lastname@example.org.