When people from other parts of the country talk about living in a desert, the first thing they usually mention is how hot they imagine it would be. Certainly, temperatures here can rise to astonishingly high levels, but Mojave dwellers know there is much more to a desert than merely the heat. I enjoy telling people that technically, the biggest desert on earth is Antarctica, with just over six and one half inches of precipitation annually. We may complain about our dearth of landscape options, but anywhere with an average temperature of 70.6 degrees F below zero is more than challenging.
Heat is definitely not the conclusive element of a desert. Lack of precipitation makes a desert. With so little water, the air and soil remain dry, limiting the amount and types of vegetation that can naturally survive there. Our water supply continues to be limited, which is visible in the “bathtub ring” around the perimeter of Lake Mead. As long as this desert continues to experience drought, we will need to conserve water.
Temperatures and moisture aside, another aspect of a desert climate that many people rarely think about is the astonishing wind that regularly sweeps over the mountains and across the landscape. Since we have relatively little plant material and few large native trees here in the Mojave, there is not much to hold the soil in place when the desert winds blow. The paltry fertility of southern Nevada soils gets even lower with wind erosion. Only the presence of a meshwork of microorganisms, a “biological crust,” keeps the local soils from blowing away entirely.
The desert is actually shaped by the wind to some degree — look at the dunes in areas where the soils are sandy. All around Southern Nevada, at Red Rock or in certain spots along I-15, you can see rock faces with horizontal etching. That shallow scarring results from windstorms carrying tiny rocks, whipping them across the surface of larger ones.
Have you ever heard that our air quality will improve as soon as we get a few days of good, fierce wind? The first time I heard that, I was baffled, but it does seem to happen — a storm blows up, carrying our dust and our pollution to wherever — maybe Utah?
We are living in a place with little water and big winds. The wind stirs up, creating the soils and removing them, shaping the rocks, and drying out the already dry air. It just makes sense that such an influential force is going to affect the plants that are exposed to it, and not only by making our desert even more arid. There are terrific adaptations that you can find when looking at desert plants. Things like cactus spines, tiny leaves, downy coverings on leaves of some plants and waxy coats on others; all of these modifications help plants conserve water despite the dry air. These are phenomenal but they are not the only ways plants that plants have evolved to survive despite the remarkable winds of the desert.
Through their roots, plants anchor themselves securely into the ground and obtain water. The deep taproots of mesquite and sagebrush allow them to probe for water far below the soil surface. One of the ways that you can keep a plant from being thrown about by the wind is always to water it deeply; not often, but deeply enough to encourage the roots to grow down along the path of the soil water.
A number of native plants are wind pollinated. Some flowers produce seeds that look as if they have wings to spread and fly away. Desert willow and saltbush rely on the wind to propagate. Unfortunately, not only desert natives are able to do this. Many of us have blown the puffball of dandelion seeds, spreading them everywhere. The wind will spread those seeds even without our assistance. Green fountain grass and sowthistle, members of Nevada’s invasive weed list, also do the same thing.
Some plants, tumbleweed for instance, have adapted their seed distribution to the winds in a dramatic fashion. It was a disappointment to discover that this weed is not a symbol of the old west, but rather is Russian thistle. To propagate, this plant literally goes whatever way the wind is blowing. Some years, I find myself pulling out that nasty, spiky stuff constantly. Russian thistle is a big shrubby annual plant attached to the earth by a relatively thin stalk. After it has produced flowers and seeds, the plant dies. That thin stalk dries and breaks. The dead plant tumbles away with its dry flowers and its multitude of seeds. As the tumbleweed goes traveling along on the breeze, it spreads its seeds everywhere.
Blowing in the wind is more than just a folksong. In the Mojave, it can be a way of life.
Email or call Angela O’Callaghan, Social Horticulture Specialist, at 702-257-5581.