Imported from the Mediterranean area for use as windbreaks, tamarisk spread quickly across the Southwest. This water guzzler—it loses five times more water to the atmosphere than an apple tree does—can actually lower the water table.
Big Bend has five seasons—winter, spring, summer, fall, and that extra blooming season that bursts out any time you have a good rain and other conditions are right. The more rain, the more spectacular the display, with flowers, buzzing insects, croaking toads, and nesting birds in a complete new cycle of regeneration. Imagine the gravel wastes of the Castolon floodplain awash with flowers—solid carpets of little white and yellow and purple blossoms on either side of the road. Running back from it are desert baileyas and grasses, with orange caltrop blowing like orange butterflies in the wind. Picture Cerro Castellan’s red flanks green, with pockets of ochre blossoms amid white heaps of volcanic ash. Imagine Mesa de Anguila’s talus slopes misted with grass, Santa Elena Overlook smelling garden sweet and so matted with little low-lying flowers that you cannot put your foot down without crushing dozens. You have never seen their like before and may not soon again, for this is the floral profusion that follows desert rains.
Most Big Bend rains come during the six warm months from May through October, but the expected rainfall may vary greatly with location and with elevation. Thus the super-dry desert between Mariscal Mountain and Castolon averages only 13 centimeters (5 inches) of rain in a year, while the Chisos mountaintops may get more than 50 centimeters (20 inches). Of course some years see more than the average, some years much less. Falling as it mostly does in torrents, very little rain penetrates the thirsty soil. The water just rolls down the slopes, rumbles through mountain canyons, gushes over a pour-off, roars along dry washes, and spreads out over lowland flats in fast-moving sheets heavy with mud. A flash flood can root up and carry off trees and other plants, animals in their burrows, automobiles and their occupants, rocks, and the very earth itself. Then almost as quickly as it came, it may go, leaving gouged and gullied desolation in its wake. Yet in a matter of days, these cracked and peeling mudflats may blossom like a garden.
The reason is that millions and billions of wildflower seeds lie dormant here, waiting for just the right combination of soil temperature and moisture to germinate and burst into bloom. Desert annuals do not store up water as the cactuses do. They do not put down deep taproots as the creosotebush does. Nor do they dress themselves in thorny, waxy, or woody shields as do the desert shrubs. Desert annuals look for all the world like their counterparts in more temperate country. They are just as colorful, just as lavish with leaves, and just as spendthrift with moisture. They live a brief, gaudy life in a hurry, completing the cycle from germination to seed production in a few, short, water-wasting weeks before the desert dries out once again. Then they pass months or even years in the seed stage, waiting for another rain and another burst of luxuriant life. This system works because the flowers produce so many seeds, and because the seeds themselves are marvelously drought resistant and programmed to sprout only at the right time and in the right place.
Each annual and perennial species has its own preferred blooming season and favored locale. The long-legged Big Bend bluebonnet may start flowering in December and keep on blooming until June. Sometimes this rangy relative of the Texas bluebonnet will bloom in such masses that the lowlands look like they have been painted blue. The daisy-shaped nicollet also likes gravelly soils, while the desert verbena does best in disturbed areas. This lavender-pink sweet william, a spring bloomer in the lowlands, appears later at higher elevations as springtime ascends the mountains. As a rule the spring bloom peaks in the lowlands in April, and species that prefer higher elevations flower a little later. Thus the bracted paintbrush begins to flaunt its red flags in June grasslands, and beautiful, deep blue tube-flowers may be seen from May to July on snapdragon vines in the Chisos woodlands. Usually the luxuriance of the spring bloom will depend on the amount of rain that fell during the preceding fall and winter, and the months of June and July are apt to show few flowers at lower, drier elevations. But with summer rains in August and September, many springtime flowers bloom again, sometimes more spectacularly. These rains also produce a bright first flowering from such summer and fall species as the low-lying, sweet-smelling limoncillo, and the broomweed that gold-plates Basin hillsides right through October and November.
Flowers
Orange caltrop
Desert baileya