Pigweed
Amaranthus retroflexus

Life cycle: summer annual
Growth habit: erect, grows 2 to 5 ft. high, branching; leaves alternate, egg-shaped, dull green to reddish
Reproduction: seed; small greenish flowers produced in dense, stiff terminal panicles; seed production from late summer to fall, until severe frost; can produce up to 117,000 seeds per plant
Conditions that favor growth: primarily weeds of agricultural and horticultural crops; adapt to a wide variety of soil types; thrive in sunny, fertile locations
Cultural control: manually remove plants before flowering occurs and seeds are produced