Toxic Parts:
oxalates, nitrates
Flower Color:
  • flower color

Time of Greatest Risk


Geographical Distribution

Curly dock distribution - United States

Related Species

Curly Dock

Rumex crispus

Yellow Dock, Curled Dock, Sour Dock, Reguette, Língua-de-vaca, Paciência, Krusskräppa, Rumex Crêpu
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Curly dock (Rumex crispus ) is a perennial broadleaf forb. Curly dock is found virtually everywhere in the world, naturalized and in some places invasive.

Curly Dock Toxic Components

All parts of curly dock are toxic to horses as it has the ability to accumulate high levels of nitrates and oxalates.

Curly Dock Identifying Characteristics

  • Height: 5 ft (1.5 m)
  • Flowers: Greenish to reddish-brown clusters of sepals, along the upper portion of the elongating stem.
  • Leaves: Ground-level leaves are dark green to reddish-purple (as they age), rosette-style, petioled, hairless, alternately arranged leaves with wavy margins. Leaves along the stem are alternatively arranged with a membranous sheath.
  • Fruit: Triangula-shaped, brown to reddish brown, glossy achenes; surrounded by a papery 3-valved or 2-winged structure.
  • Stems: Typically reddish, thick, hairless, ridged, and unbranched.
  • Root system: Large, yellow to orangish, fleshy taproots.


  • Listlessness
  • Dullness
  • Incoordination
  • Weakness
  • Coma
  • Excess Salivation
  • Tremors
  • Recumbency
  • Sudden Death


MECHANICAL CONTROL: Mowing will prevent seed production and reduce top growth. Tillage that completely destroys the taproot is effective.

CHEMICAL CONTROL: If applied in the spring it will control seedling plants. Herbicide application in the fall is the best timing for controlling established plants. Herbicides that contain glyphosate (> 1.25lb ae/A at bud to early flower stage or in the fall after a light frost); thifensulfuron (>0.33 oz ai/A); tribenuron (>0.1875 oz ai/A) plus thifensulfuron 2,4-D, or MCPA, aminopyralid, bromoxynil, or clopyralid are effective at controlling curly dock.