What’s my point? No matter what our senses tell us…spring is on its way. Nature always prevails. Once you read how plants have adapted to this harsh desert environment, it might put our crazy pre-spring weather into perspective.
And what are those crazy harsh conditions? Well…
- Very little water (the average is 8 inches per year)
- Extreme fluctuations in temperature (sub-freezing winter lows –lowest temperature on record is a -25°F — to an average of 95°F in July and August)
- Alkaline, nutrient poor soils with a high gypsum content(hydrous calcium sulfate)
- Highly mineralized ground water
- Strong spring winds, occasionally becoming gale force
- Being buried by moving 20-foot dunes — the most active dunes move 30 feet per year.
Plants manage. In fact 60 species of plants have adapted to these conditions.
The gracious elegant soaptree Yucca (Yucca elata) rapidly elongates its stem through moving dune, keeping its head (leaves) above sand. Imagine a plant being able to grow up to foot per year in this arid climate!
The tenacious skunkbush sumac (Rhus trilobata) also extend their stems as well as sending out deep entrenching roots. Eventually the roots compact and stabilize the gypsum leaving the shrubs soaring above 20-foot pedestals when the dune moves on. I wouldn’t have believed unless I saw it with my own eyes. Check out the photo…with no PhotoShopping! Other plants left on pedestals in the trail of a moving dune include and hoary rosemary mint (Poliomintha incana) and salt cedar (Tamarix gallica).
The determined Rio Grande cottonwood (Populus fremontii var. wislizeni) grows to the size of large shrub rather than a tree in gypsum sands. And when the dune starts to bury it…it regenerates by forming a plant hundreds of feet away by suckering (adventitious shoots on roots). When the going gets tough, Rio Grande Cottonwood picks up its bag and moves away.
As you would expect, all the plants growing here are drought tolerant and grow on nutrient poor alkaline soils.
Twenty-five species of grass grow in white sands. And how do these grasses deal with little water and salty conditions? Alkali Sacaton’s (Sporobolus airoides) tough, coarsely fibrous roots grow up to 20 ft to tap into the saline underground water table. Alkali sacaton extrudes the excess salt out of its leaves. Incredible!
What really surprised me was the presence of lichens and cyanaobacteria in the desert. Here, the desert lichen and cyanobacteria interact to form a living CRYPTOBIOTIC CRUST on the soil surface, which protects the soil from erosion, adds nitrogen and helps the soil to retain moisture.
Is there possible applicability of this biological dynamic duo in our gardens? It’s not that far-fetched. Mycorrhizae (fungi/plant interaction) are now used as garden product in our gardens…maybe lichen and cyanobacteria combos will be available for parched soils in the future?
ID of Rabbitbrush (Chrysothamnus nauseosus) kindly named by Mani Dylan of Santa Fe, New Mexico. Thanks to Ann Haas for the Facebook recommendation!