Big sagebrush (Artemisia tridentata) is a dominant, native shrub defining the sagebrush steppe ecosystem across the Western United States. While it is valuable for wildlife and soil stabilization, excessive cover often becomes a target for land managers. Dense sagebrush significantly reduces forage for livestock and increases the risk of high-intensity wildfires due to the plant’s volatile oils. Effective control is necessary to meet land management objectives, such as restoring native grasslands or mitigating fire hazards. This requires a strategic approach tailored to specific site conditions and desired outcomes.
Mechanical Removal Techniques
Mechanical methods involve physically disrupting or removing the sagebrush plants and are best suited for smaller areas or sites where chemical use is restricted. Since big sagebrush does not sprout from its root crown, destroying this part of the plant is necessary for successful control. Techniques like plowing or disking are highly effective, as they cut and uproot the entire plant, though they are limited to flat, rock-free terrain.
Chaining, which involves dragging a heavy anchor chain between two tractors, is often used on larger, more rugged areas. This technique works best on older, more brittle plants, typically in late summer or fall when the brush is dry and the soil is firm. Mowing or rotobeating removes the above-ground biomass and is an effective short-term control measure used to reduce fuel loads. However, mowing alone may not provide long-term control, as it can miss younger plants or fail to destroy the root crown completely.
Chemical Control Options
Chemical control offers an efficient way to manage large sagebrush infestations, particularly in remote rangelands. The success of chemical treatment depends heavily on selecting the correct herbicide and applying it at the optimal time. Herbicides like 2,4-D, a selective broadleaf killer, are commonly used and target the plant’s foliage.
For maximum effectiveness with a foliar application like 2,4-D ester, treatment should occur in the spring when the sagebrush is actively growing. Other chemicals, such as picloram or tebuthiuron, are soil-active and offer longer residual control. Tebuthiuron is typically applied as dry pellets in the fall, allowing winter precipitation to move the chemical into the root zone.
It is important to adhere to all product labels and local regulations before applying any herbicide. Soil-active treatments can remain active for extended periods, sometimes up to seven years, which may temporarily injure desirable perennial grasses if not applied when they are dormant. Application methods, whether aerial or ground-based, must carefully consider weather conditions and drift retardants to minimize damage to non-target plants or sensitive areas.
Managing Sagebrush Through Grazing and Fire
Targeted grazing, using livestock like sheep and goats, provides a biological method to suppress sagebrush, especially on young plants or in areas inaccessible to machinery. Goats are natural browsers that can be concentrated in small enclosures for short periods to apply high grazing pressure on the woody shrubs. Persistent browsing of sagebrush foliage stresses the plant, reducing its vigor and competitive ability against grasses.
Prescribed fire is a powerful tool for clearing dense, mature stands of sagebrush, which is highly susceptible to fire due to its volatile oils and inability to sprout after being top-killed. Successful prescribed burns require specific conditions, including an adequate understory of native perennial grasses to carry the fire and compete against post-fire invasive annuals like cheatgrass. Following a burn, land managers must exclude livestock for at least one to two years to allow surviving perennial grasses to regain productivity and produce viable seeds. This deferment ensures the recovery of the understory and promotes a resilient plant community.
Long-Term Revegetation and Prevention
Successful sagebrush control requires implementing a plan for long-term revegetation and maintenance. Sagebrush produces vast quantities of seeds, which remain viable in the soil, leading to re-infestation. Seeding the area with native perennial grasses and forbs is critical to occupy the space and resources previously used by the sagebrush, suppressing the germination and establishment of new seedlings.
Seeding is most successful when performed in the late fall, allowing the seeds to be naturally cold-stratified over winter for spring germination. Competition from a dense stand of established perennial grasses can suppress sagebrush seedling recruitment for an extended period. Managers must continuously monitor the site for new sagebrush seedlings and be prepared to apply follow-up control measures, such as spot-spraying or light grazing, to prevent the re-establishment of a dense sagebrush canopy.