Big Bend National Park is home to over 1300 plant taxa (about 1200 species). Hundreds of these species and varieties are showy, fragrant, or unique-looking enough to be generally categorized as “wildflowers”. In the Big Bend, we usually have two major flowering periods per year – spring and late summer. The spring flower season, because it depends largely on the amount and timing of winter precipitation, is less predictable than the summer season, which is fueled by the dependable summer monsoon.
Many annual plants like bluebonnets and some mustards will only bloom in early spring. The majority of the 46 cactus species in the park bloom in mid to late spring. Many of these cactus species produce very large, showy flowers in varying shades of yellow, red, pink, and purple. The yuccas, including the impressive giant dagger, usually flower February-April. Many shrubs and small trees, such as the fragrant yellow huisache in the southeast part of the park, and the bright purple fruity-smelling Texas mountain laurel also bloom in March and April. In March and April, bright red bunches of flowers emerge at the ends of the spiny whip-like branches of ocotillo and provide nectar and pollen for hummingbirds, bees, and butterflies. The spring flowering season frequently starts in late February along the Rio Grande and proceeds upslope to the foothills of the Chisos Mountains by late April.
The late summer flowering season is dominated by members of the sunflower family. These plants are sometimes called composites because the “flower” is actually a tightly clustered group of very small individual flowers. Most summer-flowering composites are yellow or white, with yellows being abundant in the Chisos Mountains. The summer season also brings red, blue, and purple true sage flowers to the Chisos. These fantastic shows can last well into the fall, before the first freezes hit the mountains. Another group of plants commonly called “desert sage” or ceniza grows in the mid- and lower elevations of the park and produces magenta and purple flowers quickly after significant summer rain storms. These are not sages (genus Salvia) at all, but are members of the figwort family.
Many plants are opportunistic flowerers and will bloom whenever it is warm and wet enough, from February through November, and even sometimes in the middle of winter. Several yellow composites, like the forbs yerba raton, dogweed, paperflower, and the shrubby skeleton-leaf goldeneye bloom almost continuously in wet years. Many thorny acacia species will produce white to yellow blooms opportunistically throughout the warm months. The most common perennial mustard in the park, the wonderfully fragrant bi-colored mustard, can bloom extensively in the spring and then again, though less spectacularly, in late summer.
Angiosperms (flowering plants) like those mentioned above are the most numerous and diverse group of plants is the park, but dozens of gymnosperms (cone-bearing plants like pine and juniper) and non-seed producing plants (ferns) also grow here, especially in the cooler, wetter Chisos Mountains. Not all “flowering” plants produce stereotypical colorful petal-bearing flowers. In fact, one of the most important and diverse families of flowering plants in the Big Bend (and the world) is the grass family. Grasses produce numerous small, reduced flowers in a wide array of flower arrangement, all well-adapted to wind pollination. Viewed up close with a hand lens or macro camera lens, these diminutive flowers can be quite beautiful when they produce flowering tillers in the rainy season.
Wherever you are in Big Bend, no matter what time of year, you are likely to find something in bloom. In the spring and late summer you may be astounded at the abundance and variety of wildflowers. But remember that this is a desert, and long dry periods are not uncommon here, so there are times when flowers are few and far between. “Drought” is a natural part of this environment, and these plants have adapted to survive the dry periods. Remember also not to pick or trample our wildflowers so that they can live, grow, and flower another day.
Did You Know?
Toll Mountain, 7415' (2260m), a prominent part of the Chisos Basin, is named for Roger Toll, an early Superintendent of Yellowstone National Park. During winters, he evaluated proposed park sites. It was in this role, leaving the Big Bend in 1936, that he was killed in a car accident. More...