Cheat grass in Springtime
From Kolob Canyons to Zion Canyon, grasses are found in most habitats, showcasing the dazzling diversity of life you might expect in a national park with 1,000 different species of vascular plants. Being wind pollinated, these not so showy flowers are well adapted to Zion’s breezy desert environment. They provide important forage for a diversity of wildlife that includes white-tailed antelope squirrels, mule deer and desert bighorn sheep. Grasses also help hold our sandy soils in place, cutting down on erosion. Many desert grasses in Zion are especially adapted for desert temperatures and are able to close the pores, or stomata, in their leaves during the hottest time of day, thereby reducing water loss.
Grasses are most visible in the spring on the canyon bottom; however, these tend to be non-native to Zion National Park. Both cheat grass (Bromus tectorum) and ripgut brome (Bromus diandrus) are native to Eurasia and are invasive in the Southwest. Unintentionally introduced into Zion in the late 1800’s by early settlers farming and grazing livestock, cheat grass “cheated” farmers out of their normal wheat crops. Perfectly adapted for life in Zion, cheat grass requires wet, cold winters and dry, hot summers. It out competes our native grasses, being more efficient at using the available subsurface water. As the name implies, ripgut brome is not something that wildlife find tasty, for it has sharp barbs on its seed heads. Park managers work to control these undesirable grasses through the use of prescribed burns, in the hopes of restoring native grass communities and reducing fire danger in the park.
On a walk on the Watchman Trail, visitors can find native desert grasses blooming in the spring. Native peoples in Zion collected Indian ricegrass (Stipa hymenoides) because of its relatively large, protein rich seeds. This wispy, delicate grass is a classic bunch grass, growing in tight clumps up to two feet tall. It is well suited for the dry areas of Zion, going dormant during the summer and then turning green again with the spring rains. After its seeds are dropped in the early summer, two papery, tan colored glumes persist. The glumes are leaf-like structures that once enclosed the seed. Another bunch grass found in similar sites in the park is the eye catching needle-and -thread grass (Stipa comata). This tall, droopy grass also likes sandy sites and has a needle-like seed head with a large awn, or tail, which is infamous for piercing animals’ skin or feet. This tail coils as it dries, working to plant itself into the earth.
Grasses can also be found in Zion’s famous hanging garden plant communities growing around seeps and springs. Here you will find the beautiful feathery jones reedgrass (Calamagrostis scopulorum). Common along The Narrows, this clump forming grass with its drooping leaves grows right out of cracks and crevices in wet habitats. Another wet site species found in Zion is the common reed (Phragmites australis). Although plume-like flower heads adorn the top of 10 feet tall stems, common reed often reproduces vegetatively from its spreading roots. Look for it on the Watchman Trail, where it forms dense stands in the wet seep the trails goes through.
Although Zion’s diverse habitats boast around 120 different species of grasses, these are not plants that we often take note of. With their subtle beauty they do not command us to look, as a sunflower might. But when we stop to pause and take a closer look, we find not only a diversity of grass species, but of textures and patterns; grasses are beauty in motion with seed heads waving to us as we pass on by.
