horseweed
noun
horse·weed
ˈhȯrs-ˌwēd 
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)
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.
—OregonLive.com, 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
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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.
—OregonLive.com, 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
Cite this Entry
“Horseweed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/horseweed. Accessed 23 Jul. 2025.
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