Palmer Amaranth

Amaranthus palmeri S. Wats.

Amaranthaceae (Pigweed Family)

▲ ▼ seedlings/young plants

▲ ▼ young plants

▲ young, maturing plant

▲ ▼ mature plants

▲ ▼ flower spikes of mature plant

▲ ▼ closer view of flowering spikes

Amaranthus palmeri S. Wats.; Palmer Amaranth: (Bayer Code: AMAPA; US Code AMPA)

Warm-season, aggressive annual weed, with upright pyramidal growth habit
Similar to redroot pigweed in appearance, except:
- Leaves have longer petioles and may also have silvery “V" marking (not always)
- Stems are not rough-textured or hairy
- Has longer terminal inflorescences without spiny bracts sticking out
- Inflorescences may be male or female
Male inflorescences often thicker looking than female plant flowers
Common in cultivated crops, roadsides, non-crop land
Can readily hybridize with other pigweeds, resulting in weeds with varying pigweed/amaranth characteristics
Can develop colonies of herbicide-resistant plants fairly easily where repeated use of one or similar herbicides is practiced--is considered one of the new "superweeds"

(Updated January 15, 2019)