HPIPM:Common yarrow

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Asterales
Family	Asteraceae
Subfamily	Asteroideae
Tribe	Anthemideae
Subtribe	Matricariinae
Genus	Achillea

Scientific Name

Achillea millefolium

Scientific Name Synonyms

Achillea millefolium var. millefolium

Common Name

common yarrow

Common yarrow (Achillea millefolium)

Compiled by Steve Lackman, Montana State University, Yellowstone County Extension

and Marjolein Schat, Montana State University from the following sources:

http://www.oardc.ohio-state.edu/weedguide/singlerecord.asp?id=1090

http://plants.usda.gov/java/profile?symbol=ACMI2

Aleksoff, Keith C. 1999. Achillea millefolium. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2008, October].

Identification and Life Cycle

Common yarrow (Achillea millefolium) is a perennial in the sunflower family. There are many common names for Achillea millefolium including bad man's plaything, bloodwort, carpenter's grass, carpenter's weed, devil's nettle, devil's plaything, dog daisy, fernweed, field hoop, herbe militaris, knight's milfoil, little feather, milfoil, nosebleed, old man's pepper, sanguinary, soldier's woundwort, squirrel tail, staunchgrass, staunchweed, thousand-leaf, thousand-seal, thousand-weed, and yarroway. Common yarrow has an extensive root system of fibrous roots that extend deep into the soil and much-branched rhizomes (horizontal underground stems) spreading horizontally. Young leaves are divided into lacey lobes with hairs scattered over the upper surface, lower surface, and edge. Initially, plants produce leaves in a basal rosette. Young plants have aromatic foliage that smells like sage when bruised. Stems are approximately 2 feet tall and either unbranched or forked above. Some plants produce hairy stems while those of others are smooth. Several stems often arise from the same root crown. Leaves are alternate (1 leaf per node), 3 to 10 inches long, lance-shaped in outline, with highly dissected segments that appear fern-like or feathery, gray-green, and covered with wooly hairs. Basal leaves are numerous and attached to the stem by way of stalks (petioles). Lacking petioles, stem leaves attach directly to the stem. Size decreases as the position of the leaf moves upward toward the tip of the stem. Leaves have a sage-like aroma. Each flower head is 1/4 inch wide and consists of 5 white or pinkish ray flowers (often mistaken for petals) surrounding 10 to 30 whitish disk flowers. Many flower heads aggregate into flat-topped clusters located at the ends of branches. Single-seeded fruits are egg-shaped, about 1/10 inch long, flat, grayish, and have whitish edges. Unlike many other species of the Asteraceae, common yarrow seeds are not topped with a tuft of hairs (pappus).

Habitats

Common yarrow typically establishes in thin soils where conditions are unfavorable for other plants. The presence of the plant in pastures is generally regarded as a sign of deteriorating soil quality. Common yarrow establishes in a variety of places such as landscapes, pastures, prairies, rocky shores, roadsides, waste areas, and field edges. It thrives in most climates, prefers dry soil, and even tolerates drought.

Impacts

Common yarrow may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed.

Biology and Ecology

Plants flower from June until October. On average, plants produce 1600 seeds per year, and seeds are reported to be long-lived in the soil. Rhizomes spread 3 to 10 inches in a typical year, which would increase a 2-foot-square patch to four times its original area. Several cultivated forms are available for purchase as ornamental perennials. Common yarrow does not survive cultivation. Where frequently mowed, the plant persists in a low-growing form.

Management Approaches

Management if fall can prevent spring growth from autumn and winter rhizome dry matter.

Biological Control

There are no biological control agents available for common yarrow.

Mechanical and Cultural Control

Rotary tilling can reduce common yarrow.

Chemical Control

Several herbicides are available that effectively control common yarrow. See herbicide labels for information on tank mixes.

Examples of herbicides that can be used to manage common yarrow

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=common%20yarrow&Start=1&results=53