Scientific Name: Amaranthus retroflexus

Common Name: redroot amaranth

Other Common Names: careless weed, redroot pigweed, rough pigweed

Habit: This erect summer annual can be found flowering from July through October.

Leaves: The alternate leaves are ovate with wavy margins. The leaves are hairy on the lower surface, along the prominent veins. The stout, hairy stem can grow up to 6 1/2 feet in height.

Identifying Characteristics: This plant can be distinguished from other pigweeds by its less dense terminal spike. The first true leaves of this plant are alternate, unlike any of the other pigweeds.

Flower Seed Head: The small greenish flowers occur in terminal spikes. Smaller spikes of flowers may be found at the leaf axils.

Seed Fruit: The glossy black seeds each form inside a 2 mm long utricle that splits open at maturity.

Where Found: This plant can be found in pastures, along roadsides, and other disturbed soils.

  • Life cycle: summer annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Amaranthaceae

  • Leaf arrangement: alternate

  • Leaf shape: spatulate

  • Leaf margin: wavy

  • Ochrea: Not Present

  • Stem hairs: has hairs

  • Flower color: green

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: has hairs; no hairs

  • Root structure: fibrous; taproot

  • Flower diameter: pencil

  • Leaf stalk: longer than leaf