Weeds and Herbicide Application
Pigweed species are most easily identified when they are nearing maturity. The flowering structures of pigweeds are relatively distinct for each individual species. The flowering structure (seedheads) of many pigweeds is a series of flowering branches with few to no leaves. They typically vary between species by their length, diameter, degree of branching and shape. At harvest time, it is helpful to correctly identify the pigweeds in your fields. This information can provide changes in next year’s weed management program to better control pigweeds.
The following are some guidelines to help with pigweed identification. It should be noted, however, that there is often physical variation within species and that crossing can occur within some species of pigweed, resulting in hybrid plants. Pigweeds will not always express specific traits of one parent species, but may express a combination of both.
"W072 Mature Pigweed Identification," The University of Tennessee Agricultural Extension Service, 05-0168 W072, http://trace.tennessee.edu/utk_agexcrop/105