Bark is better than the bite of a water bill.

I have been landscaping most of my life. As a child in Florida, I was able to grow tropical plants as Florida has ample rain. I moved to California and everything I knew about landscaping got a rude awakening. The plump queen palms I remembered as a child were replaced by scraggly, thirsty palms whose fronds drooped from the lack of humidity. I found myself exposed to many drought tolerant plants and even in the 80's there seemed to be a shift toward native California plants and drought tolerant ones as well. 

I saw the rise of drip irrigation and watched it take hold. It is now rather common. One thing I have been using with great success is the use of bark. Yes, bark has been used for decades to make the plants pop with it's consistent color and to a certain degree it holds moisture. As I am asked increasingly to rip out grass, People are coming to appreciate large expanses of gravel or bark in place of the lawn. On my own lawn, which I removed eight years ago, I put down landscape fabric and then added a much thicker layer of bark than normal. I am careful to not bury tree trunks, but in open areas, a thick layer of bark keeps the soil underneath moist for weeks at a time even in hot weather. It also keep the reappearance of weed cloth from happening due to foot traffic. I am well known to the tree trimmers for asking for tree bark. Sometimes the bark is quite nice and I only have to pull a few odd sticks out. Many tree trimmers have to pay to dump their bark. I have found it quite easy to get them to dump a load in my driveway for free. A cubic load of bark from a nursery costs between $40 and $50 dollars. I remember when is was well over a hundred degrees and I was digging in the bark I hadn't watered in a week. Four inches down it was clearly still moist. The one trick of adding thick layers of bark to an existing garden is one of the most effective tricks for retaining moisture and preventing evaporation and the baking of the soil  surface. By keeping the soil moist longer, roots can grow non stop making trees and shrubs more drought tolerant in the future because they have a large healthy root system. When the soil bakes dry, plants are stressed and roots near the surface die back.. In addition, the bio activity of moist bark allows beneficial organisms and fungi to flourish, further nourishing your plants and adjusting the ph as it slowly degrades.