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Weed Prevention and Management Guidelines for Public Lands


Certainly the best way to control weeds is to prevent them from taking root or becoming established in the first place. Some guidelines for preventing weeds from entering public lands and how to prevent them from spreading to new uninfested areas are listed below.

* Preventing introduction through contaminated seed, feed, mulch, gravel or fill.

1. Seed

Seed contaminated with noxious weed seeds can be prevented by requiring that the seed be labeled in compliance with the California Agriculture code. In addition to having the correct label, the seed should be required to be free of noxious weeds and the label should so state. Never buy uncleaned field run seed right off the harvester, even though it might be cheaper.

An even better way is to collect seed on the land and use local native seeds for planting. This is the ideal, because you are using local genetics, and are guaranteed that no noxious weeds will be present, unless of course they are your own.

Think twice about seeding in the first place. Why are you reseeding? Is the erosion potential so bad that seeding is required? Why won't the natives come back? Perhaps seeding should only be done in graded areas or areas where it's known that damage will occur if seeding is not done.

Lots of weed infestations have occurred through poor contractor performance, or failure to provide adequate specifications as to seed quality. Make sure to specify that seed must be free of noxious weeds. Be sure that the seed bags are inspected before the seed is applied in the field. Are you getting what you ordered? Require the contractor to load the seed, mulch, fertilizer, etc., under your inspection, because then you know what you are getting. Be sure to check the amount applied per acre verses what the contract calls for.

2. Feed

One of the best ways to prevent introductions of weed pests onto public land is to prohibit livestock lessees from supplemental feeding while his livestock is grazing on public land. If this is not possible, then supplemental feeding should be in one place only so that if weeds show up, they are at least confined to one area, and eradication will be easier.

Noxious weeds can also be introduced in livestock dung. One way to prevent this is to require that livestock be kept in a holding field for 24 to 48 hours before they are released into the open range. Local livestock or stock that is part of a familiar pattern every year wouldn't need confinement holding. If livestock is from all over or from questionable origins, or if they might have been fed poor quality hay, then holding pens are a good idea.

Controlling weeds that are dispersed in bedding in trailers and hay fed to horses both for working horses and recreation is a tough problem. One suggestion is to ask the horsemen where they purchase their hay and straw, then arrange for the supplier to sell noxious weed-free hay and straw. Local Agricultural Commissioners or Cooperative Extension Agents may be able to certify the hay or straw as being noxious weed free. Easier yet, but less effective, would be to require that the hay and straw be free from the local important weed of the area (for example yellow star thistle). Another suggestion, if local suppliers are unavailable, is to promote the use of pelletized feed. The processing involved to make this feed destroys most of the viable weed seeds present.

3. Mulch (straw, chippings, etc.)

Mulching eroded areas, bare areas, sandy roads, new construction sites, etc., is a necessary management practice. Unfortunately, mulch materials can contain weed seeds.

Many construction projects have specifications for mulching and seeding. Poor specifications and/or poor contractor performance can allow noxious weeds to be brought in through contaminated mulch. Write good specifications and inspect all materials before they are applied.

The best way to prevent weed invasion in mulch is to hire a contractor to cut and bale grass growing locally on public land. This material would be known weed free, and there would be added benefit in that local seeds in the grass would germinate and would be native or at least local.

Another way is to chip brush either in-house or by contract from local and native plants growing on public land. The same benefits would be derived as from local hay baling. Never allow the local tree trimmer or gardener to deliver free chippings to your site. They are almost guaranteed to bring in unwanted trees, shrubs, and weeds.

Rice straw should be more weed free than oat, barley, or wheat straw, especially in dry range areas. If possible require the rice straw to be free from perennial peppergrass. Oats, barley, and wheat straw can be contaminated with yellow star thistle. If possible buy local straw where the supplier may know if the ranch has yellow star thistle.

Always monitor sites where seed, feed, hay, straw, or mulch has been applied. If weeds do appear, eradicate them before they can seed. If this was a big contracted project, both the environmental document and the contract specifications should require the contractor to maintain the site weed free for a specified time. Inspect the contract and make the contractor do his job.

4. Gravel or fill

When constructing or maintaining roads, inspect gravel pits and fill sources to identify weed-free sources.

* Preventing introduction through movement of animals, people, or machinery.

1. Animals

In range allotments that have both weed-infested and relatively weed-free areas at moderate or high ecological risk, prevent movement of animals from infested to noninfested areas after weed seed set. In order to prevent excessive soil disturbance at salt licks, salt should be kept in containers and moved periodically. Revise special use permits and allotment management plans to require weed prevention and management.

2. People

People can track weeds from infested areas to non-infested areas without knowing it. Ideally, trailheads should be signed with weed awareness and weed prevention techniques. Changes in the season and/or type of recreation use may be necessary to reduce or contain the spread of noxious weeds. Designate weed-free trails and campgrounds in priority areas.

3. Machinery

Movement of uncleaned equipment or machinery from a noxious weed-contaminated area to a non-contaminated area should be restricted. This includes equipment or machinery used for or by construction, recreation, agriculture, forestry, fire prevention, oil and gas exploration and production, utility companies, mining, and tourism. All off-road equipment should be cleaned of all mud, dirt, and plant parts before moving into relatively weed-free areas.

* Preventing introduction through minimizing disturbance.

Surface disturbances need to be minimized as much as possible on all lands, including fire suppression activities, construction, reconstruction, and maintenance activities and all land uses. In areas known to be prone to infestation when disturbed, require revegetation of native species immediately after the disturbance has occurred. Land users need to be required to follow through to successful vegetative recovery.

* Preventing introduction through proper planning

Include weed prevention and treatment in all mining plans, oil and gas activity plans, and sand and gravel plans. For mineral activity, retain bonds for weed control until the site is returned to desired vegetative conditions. Ensure that weed prevention is built into timber management project designs. Recreation permits should include weed prevention guidelines and/or information on weed species present. Include weed-risk considerations in environmental analyses for habitat improvement projects. All land tenure adjustments should include an assessment for weed control. Include weed prevention stipulations in all rights-of-way authorizations.



The best time to eradicate noxious weeds is before they get established in an area. Early detection of newly introduced weeds is the best way to prevent establishment. These early detection and eradication efforts should be likened to fire control: new spot fires are quickly extinguished before they can spread. Early detection programs should include:

* Weed identification and training sessions

These should be offered for field employees, user groups, adjacent landowners, other agencies, and interested members of the public. These sessions should utilize local Ag Commissioners, Cooperative Extension agents, and other knowledgeable sources. Have a copy of "Weeds of the West" (published by the Western Society of Weed Science) in each office for a weed identification reference, and have multiple copies of the "Weed Handbook" (published by Wyoming Weed and Pest Council) for field use.

* Weed location mapping

A map of the area should be located in all field office for the field employees and the public to document sites of noxious weeds (these sites should be verified). Encouragement and incentives should be offered to staff members and others who participate in identification and reporting of noxious weeds. Be sure to contact Coop Extension Agents and Ag Commissioners for known weed areas. Once new infestations are verified, quick response is required in order to eliminate the weed before it spreads. For those areas with ongoing control efforts, locations should be entered into a Geographic Information System (GIS) if possible (follow the guidelines in the "Guidelines for Coordinated Management of Noxious Weeds in the Greater Yellowstone Area" (USDA & USDI 1992))

* Determination of high priority areas

Certain areas may be more vulnerable to disturbance or weed invasion, and should be considered high priority areas. These areas should be clearly marked on all weed maps and should be inventoried whenever possible. Cooperate with adjacent landowners and other agencies in order to coordinate early detection efforts around high priority areas.


Educating personnel as well as the local landowners and users is essential for an integrated approach to weed prevention. The more knowledge exists about weed issues, the more support there will be for weed control efforts. An education plan should include:

* Weed tours

Tours are invaluable tools for updating managers and others on the progress of noxious weed management and the methods being used. These tours should be publicized as much as possible, and can incorporate "pulling parties" with free food for those attending. Local schools, youth groups, environmental groups, user groups, and the local press should be invited.

* Employee meetings

It is important that all levels of management be aware of the weed problem on public lands. General meetings that focus on noxious weeds and feature weed videos (such as "Explosion in Slow Motion: Weeds on Western Lands" and "Enhancing Resources Through Integrated Weed Management Systems") are good ways to spread the word. It may be useful to have some brief identification training at these meetings as well.

* Outreach programs

The local public needs to be kept informed about the weed problem in order to keep interest and involvement up. Brochures and/or flyers should be periodically distributed, as should brief news releases.


Despite tight budgets and lack of personnel available to conduct inventories, there are certain activities that are feasible:

* Cooperative inventories

Inventory information should include the entire local area, not just public lands under your agencies jurisdiction. Cooperative agreements with state and county agencies responsible for conducting weed inventories/mapping should be developed whenever possible. Permittees and user groups may also be willing to conduct weed inventories.

* Inventories as part of assessments

Whenever assessments of the health of public land are required, make sure that noxious weeds are included in the process. For example, as part of the implementation of BLM's standards and guidelines for rangeland health, there is a need to inventory and identify noxious weed infestations to be able to assess rangeland health conditions and set management priorities.

* Inventories of high priority areas

Once you have determined which areas have high priority for prevention and early detection, those areas should be inventoried periodically, especially after any disturbance.


Provisions for noxious weed management should be a part of all funded or authorized activities. The following strategies are recommended:

* NEPA documentation

Incorporate noxious weed management into all NEPA documents (e.g. projects, coordinated RMPs, and activity plans). Include an analysis of the potential for weed spread and establishment as an environmental consequence of proposed actions as well as measures and stipulations to minimize or avoid the spread of weeds.

* Weed Management Plans/Areas

Develop Weed Management Plans for high-priority areas using the strategies found in the "Guidelines for Coordinated Management of Noxious Weeds in the Greater Yellowstone Area" (USDA & USDI 1992). If those high priority areas are surrounded by varied ownership patterns, and would be best managed at the regional level, try to create Weed Management Areas. Weed management within these areas would be done cooperatively, and would involve all landowners.

* Activity Plans

Ensure that site-specific monitoring objectives are included in activity plans to address infestation and control of noxious weed species.