War on Weeds—weeds are everybody’s problem

Common Yarrow (Achillea millefolium) is a native perennial forb found throughout the United States. Found in lawn areas, around planting beds, in mildly disturbed soils of grasslands and open forests. Common Yarrow has been used by several tribes of the Plain region of the United States including the Pawnee and Chippewa tribes in medicines. The Pawnee used the stalk in treatment for pain relief. The Chippewa used the leaves in a steam inhalant for headaches. They also chewed the roots and applied the saliva to their appendages as a stimulant. The Cherokee drank a tea of common yarrow to reduce fever and aid in restful sleep. For all the benefits of Common Yarrow, it can become invasive in some regions or habitats and may displace desirable vegetation if not responsibly managed.

Common yarrow produces one to several 8- to 16-inch-tall stems. Leaves are evenly distributed along the stem, with the leaves near the middle and bottom being the largest. The feather-shaped leaves have varying degrees of hairiness. Leaf blades are lance-shaped in outline but are finely divided. Overall leaf dimensions range from ¼ to 1 ¼ inch wide by 1 ¼ to 6 inches long. Flower heads have a flattened dome shape with 10-20 ray flowers. Flowers are white to yellowish white.

Integrated Pest Management (IPM) Options:  

• Prevention – Learn to identify this plant. Never transport unknown plant material. Maintain maximum turfgrass vigor and density through appropriate management practices. 
• Mechanical – Effective control must target both aboveground and underground plant structures. Hand-pull plants in lawn areas prior to flowering. Mow or cut plants to prevent developing seed heads. Mechanical removal of aboveground foliage will not kill underground plant parts; manually remove underground structures to prevent re-sprouting.
• Chemical – Spot treatments with appropriate post-emergent herbicides when the plant is actively growing with follow-up treatments when plants re-sprout may be necessary to prevent spreading structures. Many restricted and non-restricted use herbicide are available, for more information visit https://pnwhandbooks.org/ then search “Common Yarrow” in the weed section. Always read and follow herbicide label directions!

Tom Jacobsen, University of Idaho Extension Educator in Fremont County. (208) 624-3102 [email protected]