Yellow Toadflax

Yellow Toadflax

Linaria vulgaris

Colorado List B - Control required in Jefferson County

Information Sheet (pdf)

General

• Family: Plantaginaceae (Plantain)
• Has been used as an ornamental but no longer available in Colorado
• Herbaceous perennial
• Introduced from Eurasia

Common names

• Wild snapdragon, butter and eggs

Habitat

• Found in pastures, rangelands, roadsides, gravel pits and grasslands

Plant

Vegetation

• Leaves are pale green, lance shaped; 1 to 2 inches long, one eighth to one quarter inch wide, waxy
• Mature plants grow up to 3 feet tall
• Produces 1 to 25 floral stems

Roots

• Lateral roots; new plants can develop from root buds 2 to 3 weeks after germination and from root fragments as small as one quarter inch long

Flower

• Color: yellow with orange throat; dense cluster of 15 to 20 flowers at the end of stems
• Season: May to August
• Size: three quarters to 1 inch long; includes a spur typically the same length as the flower

Seed

• Each plant can produce up to 30,000 seeds
• Seed matures from July through September
• Viability and germination are low

Seedling

• Early May, some fall germination possible

Reproduction

• Mainly vegetative; also by seed

Control

Biological

• Calophasia lunula, a defoliating moth
• Eteobalea intermediella, a root-boring moth
• Mecinus janthinus, a stem-boring weevil

Chemical

• View Information Sheet (PDF)

Cultural

• Fertilization to promote grass cover
• Prevention - maintain health of site
• Removal - not effective unless done the first year plants germinate; otherwise this will fragment the roots and give rise to many more plants
• Re-vegetation of highly disturbed sites

Mechanical

• Burning - Not recommended; areas disturbed by fire are susceptible to invasion due to lack of competition from desirable plants
• Grazing - Not effective; intensive grazing contributes to conditions that help spread plants; may be toxic to livestock
• Mowing - Not recommended

More Information

• Colorado Department of Agriculture

Use all chemicals according to the manufacturer's label. No specific recommendation or endorsement is made or implied by listing methods or products.