Editor's note: Spring washes across national parks with riotous blooms of flowers. One such bloom is getting started at Big Bend National Park in Texas, and George Miller, who has written both a guidebook and smartphone app to wildflowers in the state, took some time to smell the flowers.

Thoughts of spring wildflowers usually bring visions of lush hills and meadows with picturesque streams. But not the desert. Certainly not arid West Texas. Yet by April, especially in years following a wet autumn, wildflowers and cacti turn the rugged landscape of Big Bend National Park into a palette of rainbow hues. And migrating birds add their colorful magic to the trees and thorn-covered vegetation.

Big Bend encompasses 1,200 square miles of the most rugged country in North America. The great horseshoe curve, or "Big Bend," in the Rio Grande embraces a mountain range, cuts three spectacular canyons with 1,500-foot walls, and creates a green ribbon of life in the parched desert. The combination of horizon-to-horizon panoramas, mile-high mountain peaks, hundreds of miles of back roads and hiking trails, and more species of cacti and birds than any other national park makes Big Bend a global treasure.

We pitch our tent in Rio Grande Village, a wooded oasis on the banks of the Rio Grande on the east side of the park. With nature trails, ranger programs, showers, and a store, the campgrounds provide a convenient bivouac for exploring the desert.

The red, tube-shaped flowers of Ocotillo attract hummingbirds like magnets. George Miller photo.

This year I left my wildflower books at home and carry my ID guide in the palm of my hand. My wildflower app Wildflowers of the Trans-Pecos covers 220 species with 1,500 photos and sorts flowers by color, into cacti and yucca, and species that occur in Big Bend.

Despite the harsh environment and inhospitable thorns, cacti produce some of the most dazzling flowers of any plant. The more than 60 species in the park begin blooming in April and flower into the summer. Button cactus and similar petit species with dime-sized blooms decorate the rocky landscape while larger species sport clusters with dozens of flamboyant flowers.

Starting on a limestone ridge near the river, we crisscross the parched hillside like miners searching for nuggets of gold. Rainbow, hedgehog, and Turk's head cacti glisten in the morning sun. A clump of strawberry cactus has so many scarlet blossoms we can hardly see the thorny stems. The magenta blossoms of cholla cacti spring from long, slender stems like flames on a blow torch.

Lemon-yellow blossoms cover the pads on head-high mounds of prickly pear. Most cactus flowers evolved with colors and delicate petals to attract insect pollinators, but not claret-cup. The rigid, lipstick-red flowers look like molded wax and make perfect landing pads for hummingbirds. In another month, thirsty desert creatures will feast on the succulent cactus fruit.

Cacti aren't the only players in the spring pageant. The ephemeral wildflower bloom depends on the amount of rain from the previous fall.

In wet years, Big Bend Bluebonnets can turn the desert hills into lush gardens. George Miller photo.

Many flowers germinate in the autumn and overwinter as tiny rosettes. In a boom or bust ecology, some springs produce few flowers, others turn the hills into a mosaic of colors.

In a better than average year wildflowers paint moist flats and protected hillsides with dazzling hues. At a broad arroyo that crosses the road to Boquillas Canyon, purple globes of desert verbena and tall clusters of pink globe mallows line the banks and lemon-yellow disks of desert marigold dot the dry wash. Delicate orange poppies, red firewheels, and clumps of purple wooly locoweed grow among the dagger-like lecheguillas. Yellow balls decorate the thorny acacia bushes like dobs of butter.

Throughout the park we've seen a few examples of the three-foot-tall Big Bend bluebonnets, but no dense displays. Now we find a hillside blanketed with the fragrant blooms. The rocky slope looks like blue spilled from the sky. In the profusion of blossoms, lanky wands of ocotillo tipped with red flowers bob in the breeze. Bees dive into the bluebonnets and, like an eager dance partner, a hummingbird weaves back and forth with the waving ocotillo flowers.

Each spring, especially the last two weeks of April and first week of May, birds migrating from Mexico begin arriving from their long flight across the Chihuahua Desert. Like a supermarket, Big Bend attracts birds with a dependable supply of water, insects and seeds, and nesting places. Of the 380 species of birds occurring in the park, more than 100 stay to nest. Eleven species of hummingbirds sip nectar from the abundant agave and ocotillo blossoms.

The brilliant red, wax-like flowers of Claret Cup Cactus make perfect landing pads for hummingbirds. George Miller photo.

We don't have to stray far from our tent to see the aerial display. Vermilion flycatchers bounce through the mesquite branches like little balls of fire. Scarlet tanagers, blue grosbeaks, and yellow-breasted chats add color to the campground and painted buntings and black-chinned sparrows flit along the grassy roadsides.

The yellow flash of a verdin on the way to its nest zips through the brush. Only a white-winged dove singing "who cooks for you" and a drumming woodpecker interrupt the desert silence.

In the distance, the Chisos Mountains with 7,000-foot peaks and forests of ponderosa pine and oak loom against the cobalt sky. Unexpected worlds reside within the universe that exists just beyond our daily routine. Worlds where the blue of the sky floods parched hillsides and desert valleys hide a jackpot of jewels. A trip to Big Bend offers the discovery of vast new landscapes, both outer and inner.

George Miller wrote the popular smart phone app Wildflowers of the Trans-Pecos, and the book A Field Guide to Wildflowers, Trees, and Shrubs of Texas. He previously wrote about visiting Grand Canyon National Park in winter for the Traveler.