Yellow Toadflax

Information

Linaria vulgaris - Scrophulariaceae Family - Creeping perennial

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Identification

Flowers: Yellow snapdragon-like flowers with orange throats, crowded at the top of the stem.
Seeds: Black to brown seeds with a papery wing, held in a capsule. Yellow toadflax can reproduce by seeds and by its horizontal rootstalks which send up new shoots.
Leaves: Light green linear leaves arranged alternately along the stem. Unpleasant smell.
Flowering Time: June - September
Life cycle: Perennial that grows 8 to 31 inches tall from creeping roots, often forming colonies.

Impacts

Invades roadsides, edges of fields, rangelands, meadows, cultivated fields and wastelands.
Yellow toadflax competes with desirable plants and reduces their yield. It is seldom eaten by livestock.

Most effective control methods

Overall, all toadflax species are difficult to control and management plans should integrate as many strategies as possible to increase potential for success.
For small infestations, or single plants, digging and monitoring for new plants is imperative.
For larger infestations, chemical applications using the herbicides Tordon 22K, Picloram, or Telar, have shown to have higher levels of success when applied to the flowering stage over multiple years. Yellow toadflax usually recovers from single applications.
Several classical biocontrol agents are available to use against toadflaxes, including a flower-feeding beetle and seed capsule weevil. Unfortunately, an ideal yellow toadflax biological control agent has yet to be identified; the approved agents discussed above can contribute to the overall erosion of the weed’s fitness, and therefore merit consideration when an integrated weed management approach is adopted against this species.

Control methods and timing

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Prevention (Prev) Monitor and destroy new plants before seed production.

Mechanical (Mech) Hand pulling, digging, cutting, mowing and tilling.

Cultural (Cult) Biological control agents, livestock grazing, and revegetation practices.

Chemical (Chem) Selective herbicides based on the plant and the specific location. Check our weed fact sheets for specific control information.

Yellow toadflax in bloom

Yellow toadflax foliage, looking straight down on the plant

Yellow toadflax: roots

Yellow toadflax: infestation

Yellow toadflax: infestation

Yellow toadflax: flowers

Yellow toadflax: seeds

Yellow toadflax: stems, foliage, flowers, and roots