When I've talked to people from other parts of the country about living in a "desert", the first thing that they usually mention is how hot they expect it to be. Of course, we know better, don't we? I love telling people that the biggest desert on earth is Antarctica. Talk about Xeriscape! We think we have limited landscape options!
No, heat is definitely not the definitive element of a desert. Lack of precipitation makes a desert. Lack of water makes the air dry; and that, of course is what limits the amount, and types, of vegetation that can naturally survive. And no matter that we've had record amounts of rainfall; our water supply is still way down, and we still need to conserve. Drought - desert - of course we need to conserve water.
But all that aside, another aspect of a desert climate that many people don't think about is the astonishing wind that regularly sweeps over the mountains and down, across the landscape. Since we have relatively little plant material, and not much in terms of big plants - not too many large native trees here in the Mojave - there's not much to hold the soil in place. The paltry fertility of southern Nevada soils gets even lower with wind erosion. The desert is actually shaped by the wind to some degree - look at the dunes in areas where the soils are sandy. And all around here - at Red Rock, 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.
And, have you ever been told that our air quality will improve as soon as we get a day 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?
So here 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. Not only by making our desert even more arid. I don't want to sound as if I'm minimizing the terrific adaptations you can find on desert plants. Things like cactus spines, downy coverings on lots of leaves and waxy coats on others - all of these help plants conserve water despite the dry air - and those are phenomenal. But that's not the only way plants are affected by the remarkable winds of the desert.
Some plants will anchor themselves really securely into the ground - like the deep taproot of sagebrush, which also allows it to probe for water far below the soil surface. In fact, one of the ways that you can keep a plant from being thrown about by the wind is to water it deeply whenever you water it - not often, but deep; encourage the roots to grow down.
A lot of plants don't try to tough it out against the wind, though. So many flowers are wind pollinated. Some plants produce seeds that look as if they have wings to spread and fly away. Desert willow and saltbush rely on the wind to propagate. Now that dandelion has started to make its appearance locally, everyone's going to get to see how those seeds blow in the wind. The newest member of the invasive weed list, green fountain grass, does the same thing.
But some plants are even more extreme. Take a look at tumbleweed. This is a plant that literally goes whatever way the wind is blowing. Such a disappointment to discover that it's Russian thistle! Actually it's not a disappointment - I've been pulling it out all over the place. Nasty, spiky stuff. What happens with Russian thistle is - when it produces flowers and seeds, the whole plant dries out. It's a big shrubby thing attached to the earth by a relatively thin stalk that breaks, and the dead plant tumbles away with its dry flowers and its gazillions of seeds. As the tumbleweed goes traveling along on the breeze, it spreads its seeds everywhere.
Blowing in the wind. It's more than just a folksong.
On a completely different couple of topics: If you're a teacher interested in participating in the Junior Master Gardener program, we're holding a training session. Call the office for more details. And, start marking your calendars, because the last week of April is Arbor Week. Henderson is really committed to this. The big event will be at the City Park, the morning of April 29.
For KNPR's Desert Bloom, this is Dr. Angela O'Callaghan of the University of Nevada Cooperative Extension.
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