Summit Outside: Sagebrush: color in an otherwise drab environment
October 20, 2012
Driving from Summit County west you see miles and miles of high desert terrain of mainly pale grey to silver-colored sagebrush. It seems a bit monotonous to see so much sagebrush, but its yellow flowers which bloom in the late summer and early fall adds color to an otherwise bleak landscape. Why does it survive in an arid harsh environments when most other plants can’t?
It is really ubiquitous! Big sagebrush and other species are the dominant plants across large portions of the Great Basin, covering some 422,000 square miles in 11 western states, and in Canada. Sagebrush is generally long-lived once it makes it past the seedling stage, and individual plants can survive over 100 years.
There are four species of sagebrush, and its genus name Artemisia is named after the Greek goddess Artemis. She was the goddess of hunting, wilderness, wild animals and protector of young girls; bringing and relieving disease of women and animals. There are a number of important medicinal plants in this genus.
Sagebrush provides food and habitat for a variety of species, such as antelope, gray vireo, pygmy rabbit and sage grouse.
There is a chemical compound in sagebrush that protects the plant from many plant-eating animals. These chemicals, at high concentrations, are toxic to the digestive bacteria in the rumen of deer and cattle. Damage to sagebrush caused by grazing herbivores, results in the release of these chemicals, which are used to signal a warning to nearby plants, so that they can increase the production of these repellent compounds, thus making them more unappetizing. Pronghorn antelope are the only large animal to browse sagebrush extensively.
Sagebrush can provide shade and shelter from the wind. The long taproot of sagebrush coupled with laterally spreading roots near the surface draw water up from deep in the soil, allowing sagebrush to gather water from both surface precipitation and the water table beneath. Some of this water becomes available to surrounding shallow-rooted plants such as a desert grasses such as Idaho fescue, bluegrass or bluebunch wheatgrass, which can be found in the space around sagebrush.
When sagebrush flowers in the late summer or early fall, they add color to the landscape. The small, yellow flowers are in long, loosely arranged tubular clusters. The fruits are seed-like and somewhat hairy. The Cahuilla tribe used to gather large quantities of sagebrush seed, and grind it to make flour.
Sagebrush can also reproduce through sprouts, an extension of the parental plant. The sprouts are connected to already healthy and associated plants, while the new seedlings will need to start anew. It is an evergreen shrub, keeping some of its leaves year-round.
Sagebrush actually does not tolerate excess water. Areas of the desert where there is water often have sharply demarcated edges where the sagebrush ends and the green area begins, which often consists of western juniper or rabbit brush.
It’s amazing how many of our local plants have herbal-medicinal or other useful properties. Daniel Moerman’s Native American Ethnobotany lists sagebrush as one of the 10 plants with the greatest number of uses.
The Native American tribes of the Intermountain West used sagebrush to prevent infection in wounds. An herbal tea made from sagebrush was ingested to halt internal bleeding caused by battle wounds and childbirth. For treatment of colds, sagebrush was used in a tea or a hot vapor bath. The Navajo used the vapors of sagebrush as a treatment for headache. The Paiute used it to treat headache and colds by burning sagebrush and inhaling the smoke. The Washoe, Zuni and Cahuilla used sage smoke to purify and disinfect rooms. The Okanagan and Colville people used sagebrush to smoke hides. Tea was made from various parts of the plant, and it was used extensively in medicine. The wood was used as fuel, and the stringy bark was used in the manufacture of ropes and baskets.
The sagebrush plant’s oils are toxic to the liver and digestive system of humans if taken internally. Generally, toxic symptoms will subside 24-48 hours after ingesting the plant.
Chemically, the active medicinal constituents of sagebrush include terpenoids (known for their aromatic qualities), which include camphor (commonly used as a moth repellent), and tannins. Tannins play a role in protection from predation, and perhaps also as pesticides, and in plant growth regulation.
Besides practical uses, sagebrush has a symbolic value, especially in Nevada, where it covers most of the state. Sagebrush is the official state plant, is featured on the state flag, and is even mentioned in the state song.
Major threats to sage brush including human settlements, agricultural land conversion, livestock grazing, invasive plant species, wildfires and climate change. The cattle industry burns large areas of sagebrush habitat to make pastures for grazing animals. Where sagebrush was the primary shrub, many species have become adapted to this habitat. The burning of the shrubs leads to habitat loss and can be very detrimental to the environment, while the destruction of native grasses by grazing and fire creates conditions where invasive plants can colonize the area.
The invasive species which has destroyed the largest amount of sagebrush habitat is called cheat grass. Since its accidental introduction in the 1890s, cheat grass has radically altered the native shrub ecosystem by replacing native vegetation, and by creating a fire cycle that is too frequent to allow sagebrush to re-establish itself. Sagebrush is not fire-tolerant and relies on wind-blown seeds from outside the burned area for re-establishment.
Joanne Stolen is retired from teaching microbiology at Rutgers University.