NAISMA Weed Free Gravel

Washington Weed-Free Hay and Mulch Program (WWHAM)

The WWHAM program is now run by the Washington State Department of Agriculture's (WSDA) Plant Services Program. You can find out current program information on their website and contact them by email or call (360) 902-1984.

Prior to 2011, the Washington State Noxious Weed Board ran the WWHAM program. This webpage contains background information on the program. Please refer to the WSDA's Plant Services Program website for current WWHAM program information.

Why is there a weed-free hay and mulch program?

Invasive plants can be introduced to wilderness via non-certified hay, mulch, straw, and raw feeds. Invasive plants outcompete native plants, degrade wildlife habitat, and reduce soil and water quality. They cause economic losses in natural areas and impact aesthetics and recreation opportunities.

While weeds can be extremely difficult to remove once established in croplands, rangeland, yards, and abandoned lots, they are especially hard to detect and then eradicate in wilderness areas.

The USDA Forest Service passed order 36 CFR 261.58(t) to help prevent the introduction of new weed seeds into designated wilderness areas and all Forest Service lands. Effective January 1, 2009, commercially processed feed pellets and/or certified weed-free straw and feed are now required for all U.S. Forest Service lands in Pacific Northwest National Forests, managed by the USDA Forest Service.

What is guaranteed by WWHAM Certification?

What is NOT guaranteed by WWHAM Certification?

What kinds of products are included in this weed-free requirement?

How can a grower get his or her crops WWHAM certified?

Are these weed-free products required if someone is passing through National Forests?

Where can I purchase WWHAM-certified hay and mulch?

Where can I learn more about WWHAM?

Please contact the WSDA Plant Services Program at 360-902-1984 or at

Download the official USDA Forest Service question and answer PDF. It contains more detailed information about the new Forest Service efforts to prevent the introduction of noxious weeds.

North American Invasive Species Management Association (NAISMA) Weed Free Gravel Information

Washington State does not have a Weed Free Gravel Program but we do encourage the volunteer use of NAISMA's Weed Free Gravel Standards. Find these standards and forms on NAISMA's website. The North American Invasive Species Management Association was formerly known the the North American Weed Management Association (NAWMA).