CHEYENNE, Wyo. – The Wyoming Weed and Pest Council (WWPC), in partnership with the North American Invasive Species Management Association (NAISMA), is excited to announce a new twine color for NAISMA certified weed-free hay. Any forage or hay certified as weed-free will now be marked with blue and orange twine or will be accompanied by either a certification form or a transit certificate.

The weed-free twine program helps limit the spread of noxious weeds through the movement of forage or hay. Many federal and state lands require certified weed-free forage to prevent the spread of invasive weeds. The new bright blue and orange colors will make it easier to identify weed-free hay.

“It’s important to use weed-free forage whenever possible,” said Larry Smith, WWPC President. “It ensures that it’s free of invasive weeds and helps offset the billions of dollars that it takes to control those weeds. It helps us keep Wyoming’s natural beauty alive.”

Noxious weeds are increasingly damaging to the landscape and livestock in Wyoming. Invasive weeds are usually unpalatable and sometimes poisonous to livestock. Additionally, the management of invasive weeds in the United States costs upwards of $130 billion dollars each year. Certifying hay or buying certified weed-free hay prevents the spread and can lower the cost of prevention.

Previously, weed-free hay was identified with purple and yellow twine. It may still be common to see the old twine color as it is phased out. The new orange and blue twine can only be purchased by the WWPC to provide to certified hay producers.

Visit to find certified weed-free hay or how to get your products weed-free certified.