horse·​weed ˈhȯrs-ˌwēd How to pronounce horseweed (audio)
: 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
: a coarse annual North American ragweed (Ambrosia trifida)

Examples of horseweed in a Sentence

Recent Examples on the Web Other native plant enemies include sow thistle; dandelions, which spread clouds of seeds once their cheerful yellow flowers dry up; tall bulky horseweed; round-leaved cheeseweed; purslane; and spurge, which blanket the ground like thick green doilies. Los Angeles Times, 13 June 2022 But after glyphosate-resistant crops had a few years to grow, farmers began to notice horseweed and morning glory and other weeds encroaching once more into their fields. Carl Zimmer, Discover Magazine, 4 May 2010 Some examples are sharp point fluvellin, velvetleaf, puncturevine, horseweed, western bittercress and oxalis., 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, 24 June 2014

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'horseweed.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1790, in the meaning defined at sense 1

Time Traveler
The first known use of horseweed was in 1790

Dictionary Entries Near horseweed

Cite this Entry

“Horseweed.” Dictionary, Merriam-Webster, Accessed 4 Dec. 2023.

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