Residual herbicides have place in soybean production

- Perennial weeds: With problem perennials like Canada thistle, pokeweed, hemp dogbane, or other problem perennials, glyphosate applied to the perennial weeds at the bud to bloom stage will have the biggest bang for the buck (or better yet in the fall). Control the annual weeds with the soil- applied residual program to allow for the slightly later more optimum post application targeting the perennials.