Weed Control Information
During summer 2023, Palmer amaranth and waterhemp, two invasive weeds were identified in Malheur County, Oregon and several Counties in Idaho. Palmer amaranth and waterhemp belong to the genus Amaranthus, which include various other pigweeds (e.g. redroot pigweed and Palmer amaranth). Both species exist in male and female forms, with male plants only shedding pollen to pollinate flowers on female plants. Both are erect annual plants. We have developed a flier that will serve as a guide to correctly identify these plants. If found, please contact Joel Felix at 208-739-2675 joel.felix@oregonstate.edu; Clarke Alder 208-989-7400 calder@amalsugar.com; and/or aadjesiwor@uidaho.edu.
Palmer Amaranth and Waterhemp Identification Flier and Palmer Amaranth and Waterhemp Trifold
Weeds present huge problems for Malheur County growers. They invade fields, impede crop growth, and can be incredibly expensive and time-consuming to manage. Malheur Experiment Station has performed numerous trials on various weed control techniques, the results of which are published every year in the station's Annual Report.
View the MES Complete Publications List, with Weed Control research reports sorted by crop.
The Station also contributes information to the Pacific Northwest Weed Management Handbook, a grower guide that includes weed control recommendations for numerous crops grown throughout Idaho, Oregon, and Washington.
Go to the Pacific Northwest Weed Management Handbook Website