from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A weedy North American plant (Erigeron canadensis) having narrow leaves and numerous small white or greenish flower heads grouped in panicles.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of various flowering plants of the genus Conyza.
from the GNU version of the Collaborative International Dictionary of English
- n. A composite plant (Erigeron Canadensis), which is a common weed.
from The Century Dictionary and Cyclopedia
- n. A composite plant, Erigeron Canadense, a troublesome American weed.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron
- n. erect perennial strong-scented with serrate pointed leaves and a loose panicle of yellowish flowers; the eastern United States
Now, Roundup-resistant weeds like horseweed and giant ragweed are forcing farmers to go back to more expensive techniques that they had long ago abandoned.
But now, as nasty invaders with names like pigweed, horseweed and Johnsongrass develop immunity to the mighty Roundup, chemical companies are dusting off the potent herbicides of old for an attack on the new superweeds.
Grey lichen grew on the cabin logs and dried stalks of horseweed and pigweed and fleabane rose from the snow in the doorways.
Farther south, in the southern needleleaf region, the transition from old field to forest begins with crab grass and annuals, proceeds to horseweed followed by broomsedge, and culminates in a seeding-in of pitch, longleaf, slash, loblolly, or shortleaf pine.
He came out upon the road slowly and stopped there, switching his legs absently with the stalk of a horseweed.
In the case of the Canadian horseweed or _Erigeron canadensis_, which is widely naturalized in Europe, the tallest specimens are often twenty-five times as tall as the smallest, the difference increasing to greater extremes, if besides the main stem, the length of the numerous branches of the tall plants are taken into consideration.
Gravel root; horseweed; knotweed; Canadian collinsonia.
Resources of the Southern Fields and Forests, Medical, Economical, and Agricultural. Being also a Medical Botany of the Confederate States; with Practical Information on the Useful Properties of the Trees, Plants, and Shrubs
In 2000, the first case of glyphosate resistant horseweed was confirmed, and this was further confirmed in cotton in 2001.
Canadian horseweed (Conyza canadensis), a weed that is becoming resistant to the weedkiller
My standard recommendation for controlling horseweed is 8 ounces of a dicamba product like Clarity tank-mixed with glyphosate or other herbicide to control other weeds present.