horseweed

noun horse·weed \ ˈhȯrs-ˌwēd \

Definition of horseweed

1 : a common annual American composite herb (Conyza canadensis synonym Erigeron canadensis) with an erect usually hairy stem and small discoid heads of yellow disk flowers

2 : a coarse annual North American ragweed (Ambrosia trifida)

Recent Examples of horseweed from the Web

Some examples are sharp point fluvellin, velvetleaf, puncturevine, horseweed, western bittercress and oxalis.

— OregonLive.com, "How to defend lawns, gardens against invasive weeds," 27 Feb. 2018
Yet tolerance to 2,4-D has already been documented in several weed species that have elsewhere become glyphosate-resistant superweeds, including waterhemp and horseweed.

— brandon keim, WIRED, "The Next Generation of GM Crops Has Arrived—And So Has the Controversy," 24 June 2014

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'horseweed.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.