Dalmatian Toadflax

dalmatian toadflax flower
dalmatian toadflax root
dalmatian toadflax plant
dalmatian toadflax leaves

Dalmation Toadflax

Centaurea diffusa

Information Sheet (PDF)


Colorado List B - Control required in Jefferson County


General

  • Family: Plantaginaceae (Plantain)
  • Grows from sea level to 9,200 feet
  • Has been used as an ornamental but no longer available in Colorado
  • Herbaceous perennial
  • Individual patches can live for 13 or more years
  • Toadflax can significantly reduce crop yields and stress native communities


Common Names

  • Wild snapdragon


Habitat

  • Found in pastures, rangelands, roadsides, gravel pits and grasslands
  • Prefers open, sunny locations
  • Tolerant to low temperatures and coarse soils


Plant


Vegetation

  • 1 to 3 inches long, 3/8 to 3/4 inch wide and waxy
  • Leaves are heart-shaped and clasp the stem
  • Mature plants up to 3 feet tall
  • Produces 1 to 25 floral stems
  • Stems are woody at the base
  • Top growth dies back in fall, prostrate stems form in the fall and during winter


Roots

  • Lateral roots are found 2 to 8 inches deep, can extend horizontally 10 or more feet
  • New plants can develop from root buds 2 to 3 weeks after germination and from root fragments as small as 1/4 inch long
  • Taproots can reach 6 plus feet deep


Flower

  • Color: yellow
  • Season: spring to fall
  • Size: 3/4 to 1 1/2 inches long
  • Typically has a spur as long as the flower


Seed

  • Each plant can produce up to 500,000 seeds
  • Remains viable up to 10 years
  • Seed capsules begin opening in July
  • Seed matures from July through September


Seedling

  • Most emerge in April
  • Some fall germination possible under optimum conditions


Reproduction

  • Seed and vegetative means


Control


Biological

  • Calophasia lunula, a defoliating moth (L)
  • Brachypterolus pulicarius, Toadflax flower-feeding beetle (A)


Chemical


Cultural

  • Fertilization to promote grass cover
  • Prevention - maintain health of site
  • Removal of prostrate stems in spring and fall reduces floral stems
  • Re-vegetation of highly disturbed sites


Mechanical

  • Burning - Not recommended; deep roots protect the plant; areas disturbed by fire  are susceptible to re-invasion due to lack of competition from desirable  plants
  • Grazing - Does not control; intensive grazing contributes to ideal habitat  conditions, helping dalmatian toadflax spread; may be toxic to  livestock 
  • Mowing- Not recommended


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