Standing outside for 14 hours every day during July and into August will stress any living thing. All plants and trees struggle to survive during the long, hot summers here in the Central Valley, but restricted irrigation during this year's extreme drought conditions has caused even more damage than usual.
As the days grow shorter and nights grow longer in late summer, plants and trees have more time to recover at night from the daytime heat. Longer, cooler nights allow plants to come out of the state of semi-dormancy that is caused by long periods of daytime temperatures above 95 degrees and nighttime temperatures above 70 degrees.
During July and early August plant growth slows or even stops and flower production ceases on most plants. The best practice during this time is to reduce or stop fertilization (plants aren't growing any way) and to continue to irrigate deeply to provide water to root systems. During nondrought years, fertilization is resumed in the last weeks of August and soil moisture levels are monitored to keep the soil consistently moist as new growth begins.
During years with normal amounts of rainfall and sufficient water reserves, the new mandatory watering schedule that restricts irrigation from three to two times weekly would not be a problem; deep, infrequent irrigation is key to encouraging plants, trees and lawn grasses to develop deeper, stronger root systems.
However, during this third consecutive drought year the new watering restrictions will mean that those gardeners who have already cut back on irrigation will find that their half-dead lawns will be more than half-dead, the scorched leaves on roses will not be replaced with new growth and roses and other perennials will not set new buds in August for the usual good September bloom. Citrus trees will lose their immature fruits without deep irrigation that keeps the soil moist below four inches and the tops of redwoods will continue to die back.
Watching plants die will be the hardest part of gardening this late summer. Don't waste too much time and water on trying to keep plants that are obviously drought stricken alive. Do try to find sources of additional water from household sources to keep invaluable shade trees alive, if not flourishing.
Fertilization will not flush new growth if irrigation is just enough to keep plants alive. Wait until spring to fertilize; even if we get late fall rains, we don't want to force new growth just before the first frost in mid-November.
Avoid using herbicides, especially on lawns, when irrigation is restricted. The chemicals will build up on the dry soil and could wash off into gutters and our water supply when the rains arrive — fingers crossed.