 I'm North Dakota Soybean Council Director Mike Slosher-Vegeli. Palmer is recognized as one of the most aggressive weed species and has invaded fields in North Dakota. It is documented as the most problematic weed in the U.S. because it grows and reproduces rapidly and prolifically, is prone to develop resistance to multiple herbicides. It can also cut yields dramatically. Correct identification of Palmer is a challenging task for growers and crop consultants because it is hard to distinguish from other pigweed species.