Return to weeds

Marestail/horseweed (Conyza canandensis) germinates throughout spring and early summer and will mature and set seed the same year. Seed that germinates in fall overwinters in the rosette stage. Plants reach heights of 3 to 6 feet, and one plant may release 200,000 seeds that disperse easily by wind. Marestail is becoming more commonly glyphosate-resistant.

Marestail.

(Photo: Robert Videki, Doronicum KFT, Bugwood.org)

Marestail flowers.

(Photo: Mary Ellen (Mel) Harte, Bugwood.org)

Management: 

• Pre-emergent herbicides prevent seed germination.
• Burn-down herbicides during seedling or rosette stages destroy young plants.

Return to weeds