Focus On: The Unpredictable Desert Spring

Arizona's desert regions are full of miracles. Perhaps the most curious lies dormant for a good portion of the year in a particle hardly larger than a speck of dust. It's a wild flower seed. Each of billions has the potential of becoming a blooming plant. It takes something of a very special kind of miracle to make it happen. For most of the year, Nature hews to a bust-and-boom regime in which drought is the rule and rain the exception. So, to survive in the dry and pitiless desert heat the flora must retreat into dormancy until another time when conditions are right.

desert spring

The perennials and woody plants become leafless and gaunt. And what foliage remains is dull, lifeless, and parchment dry. The cacti, which also produce spring flowers, survive by their ability to draw in moisture through their roots, change it chemically into a mucilaginous juice, and store it in cells within their bodies for a long time. Saguaros are sustained by a broad network of shallow roots that hold the plants upright and capture as much moisture as possible from infrequent rainfalls. Moisture is carried from their roots and channeled to their spongelike skeletons that expand accordion-like in girth as they swell with water and shrink during seasonal dryness. Yuccas store moisture in their trunks and stiff fibrous leaves. And the ocotillos have developed a mechanical arrangement so that when the soil is moist their foliage transpires, and when the soil is dry their leaves drop off.

happening determined by cool soil temperatures, but mostly by rain, about an inch in autumn and another two in November and December. This is what miraculously transforms the desert landscape into a verdant garden, where the poppies, penstemon, and prickly pear renew their tenuous hold on life again. The spectacle of spring may be as short as 30 days or as long as 45. Still, in that short time, with their brilliant, tender blooms, they give an inspired and passionate performance for all to see in the vast desert regions of this fragile land. In a given year and location, plant species in bloom may predominate over one area and not the next. The flowering facts are determined by soil type, texture, slope, and exposure. Some species prefer the sun-baked earth, others bloom better in dry washes or on the open rocky slopes. Still others require the shelter of a meadow shaded by trees really no larger than a tall bush, or a streamside where moisture is constant. In the lower Colorado River Valley, the hottest, driest, and most spectacular blooming region of the Sonoran Desert, and the Arizona Upland-which together extend from Yuma to Safford and north toward Wickenburg-there is a good bloom only once or twice every decade. An exceptional bloom occurs once every 30 or 40 years. But every year there is at least something to see.

Spring is the Sonoran Desert's one moment of glory and an opportunity to award itself. And it does so in lavish abandonment as flowers unfurl their beauty on the mountains, canyons, and valleys all over the state. Flowering periods of common desert plants follow a regular pattern varying by about 10 days from year to year. Late February is curtain time for the sand verbena, whose white and pink flowers open at night expelling a sweet perfume. The scent lasts until the first rays of sunlight. The annual bladder-pod covers extensive areas of the desert with yellow flowers. As does the loco-weed, which blooms purple and can cause some livestock grazing on it to "go loco." February is also time for the evening primrose, whose large white flowers open at night, lasting through evening, then turning pink as they wilt the following day. The penstemon, which sends out long wands of scarlet from the desert's streambeds to its steepest trails, has flowers only on the upper half of its stem. In some years, fairy-dusters offer a pink powder puff show, accompanied by yellowflowered brittlebushes, so named because their stems break easily. Early March brings the desert hyacinths and wild onions into bloom. Desert mallows awaken with showy flowers, deep red to apricot. Filarees come alive along the roadsides with excellent lavender colors.

The annual wild flowers react in their own special way to the ever-present threat of extinction by storing energy in their underground seeds which may lie dormant in the soil for decades, holding off germination until survival to maturity is a certainty. Only when internal chemistries signal, do they sprout from the soil, flower, bear new seeds, and then disappear quickly into the dust. They live only for the moment. Arizona's spring wild flower show is a

desert spring

And the Joshua trees, whose greenish-white flowers hang in dense heavy clusters, get ready to bloom.

By late March, the peak wild flower sea-son arrives for low growing plants. Fiddle-necks offer coiled, orange-yellow flower clusters. Desert chicory, a weak-stemmed annual with white, dancing blooms, can be found in the shade of canyon shrubs. Gilias skyrocket into spectacular reds. Gold-fields blossom everywhere in yellow. And lupines, certainly among the best-known wild flowers of the Southwest, bud in deep blue.

The latter part of March is also time for the crimson monkey-flowers, one of the species sure to be present in shady seeps and along permanently-running stream-beds. Owl-clover, whose masses can be purple or red, appear out of the blue. Phacelias, or scorpion weeds, as they are commonly called due to the coiling of inflorescence in some species resembling a scorpion's tail, are here and there, varying in their abundance according to the amount of winter rain.

Also at their colorful best are tackstems, graced by bright yellow flowers; verbena, topped by a flat cluster of lavender blooms, and gold poppies, whose familiar yellow blossoms ignite the desert floor.

The spectacle of spring abounds in April as plant life continues to be renewed again. Hedgehog and beavertail cactus are among the first succulents to flower with scarlet to magenta blooms. Then come cholla and prickly pear, dressed in waxy, yellow hues. Desert marigolds, common on road-sides, also bear yellow blossoms.

Late April brings the blue paloverde into yellow bloom and gives way to the ocotillo's flowers, bright orange on the succulent's branch tips.

May is the month for woody plants like coral-bean, desert senna, and iron-wood to flower. The average bloom date for saguaros is about May 20, but it can happen sooner.

In early April buds appear in vertical rows at the tips of the cacti's main stems and branches. About six to eight weeks later, clusters of waxy white flowers, four inches in diameter, begin to encircle the crowns of each trunk and arm. The blosSoms are Arizona's official state flower. Saguaros don't produce their first flow-ers until they reach maturity at 50 to 70 years, and are 16 to 22 feet high.

June, the driest month of the year, marks for most wild flowers the end of the springtime show.

But for a few woody plants and succu-lents, like ironwoods, desert sennas, and creosotes, there's still hope. Also for the soaptree yucca, sotol, night blooming cereus, organ pipe cactus, old man cactus, teddy bear, and cholla cactus, thanks to their special ability to store moisture.

This is the spectacle of spring. It is what lures the close observer, the beauty seeker, the botanist, the young and the old to the desert. It is the attraction that causes people to travel miles to paint, to photograph, and to just admire.

Dayna Lynn Fried, a newspaper horticulture reporter, has lived in Arizona and written about its plants for five years.

Additional Reading

Discovering the Desert, by William McGinnies, University of Arizona Press, Tucson, Arizona, 1981.

Grand Canyon Wild Flowers, by Arthur M. Phillips, III, Grand Canyon Natural History Association, Grand Canyon, Arizona, 1979.

The Cacti of Arizona, by Lyman Benson, University of Arizona Press, Tucson, Arizona, 1981.