Seedling
Bright green, with slightly hairy leaves, leaves may be twisted, roots fibrous.
Mature plant
Quackgrass has coarse-textured (wide) blue-green leaves with long, clawlike auricles (appendages where the leaf blade meets the stem).
Root fibrous roots emerge from rhizomes. Rhizomes about 1/8 inch across, branched, with pointed tips, creamy yellow, tough, usually 2 to 8 inches deep.
Stems erect, jointed, branching from the base, 1 to 4 feet tall, smooth.
Root structure description
If you pull up quackgrass, the long white rhizomes will be visible.