Know Your Winter Annual Weeds

August 22, 2007 in Uncategorized

Winter annual weeds will start to germinate now and continue through the fall. Winter annual broadleaf weeds include common chickweed, jagged chickweed, henbit, purple deadnettle, field violet, annual speedwells (corn and Persian speedwells), marestail, and mustard family weeds including wild mustard, wild radish, yellow rocket, and shepard’s purse. Winter annual grasses include annual bluegrass, annual ryegrass, downy brome, cheat grass, and other annual brome species. These will be weeds that compete in the fall, winter and early spring with alfalfa, small grains, and grass hay fields. Scout these fields in the fall and determine if fall, winter, or spring control programs will be needed.

Common chickweed seedling
Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection

Purple deadnettle seedling
Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection
Henbit seedling
Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection

Marestail or horseweed Seedling
Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection
Wild mustard seedling
Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection

Annual Bluegrass Seedlings
Photo from Weed Management in Nursery Crops, Oregon State University
http://oregonstate.edu/dept/nursery-weeds/weedspeciespage/annual_bluegrass/annual_bluegrass_page.html

Downy brome seedling

Photo From Online Pacific Northwest Insect and Weed Management Handbooks
Photos Credit: Oregon State University Jed Colquhoun and Larry Burrell photo Collection