Horseweed

Conyza canadensis

Photo of Horseweed
Photo by Dr. John Meade, weed scientist emeritus
Rutgers NJAES Cooperative Extension

Horseweed has been called marestail in the past. The scientific name used to be eupatorium canadensis. It is a winter annual germinating in September and remaining as a small rosette through the winter. This growth stage is responsible for the name, buttonweed. The seeds blow easily and it is a widespread weed problem in containers as well as field nurseries. It thrives on no-till fields and must be controlled prior to planting.

Additional Images


  1. Rutgers
  2. Executive Dean of Agriculture and Natural Resources
  3. School of Environmental and Biological Sciences