Amaranthus palmeri (carelessweed) is a
dicot herb native to the United States and found throughout most of the lower US. The entire Amaranth family is known as pigweed. Amaranthus p. is very hardy but is frost tender. It can handle most any soil ranging from sandy to loamy to clay. It also grows in soil pH ranging from acidic to alkaline easily. Amaranthus p. requires full sunlight and cannot grow in shaded areas. It also needs moist but well-drained soil.
The Amaranthus palmeri is
monoecious, flower
panicles (see right) are either male or female and are found on the same plant but different branches (see above). It pollinates with wind, is self-fertile, and is an
annual. Its seeds sow in late spring and can germinate rapidly if the soil is warm. An overnight temperature drop aids in germination as long as temperatures are not freezing. Cuttings of the plant root easily. Amaranthus p. blooms in summer/fall time and can grow to be 6.5 feet high. The stem below the cotyledon (as a seedling) does not have hair and can have a reddish tint. Its
taproot is often reddish and the leaves do not have hair (unlikely many other genus members). The leaves have prominent white veins on the underside of the leaves (also unique to Amaranthus palmeri) and range from 2-8 inches long. The very top of the adult plant contains panicles 6-18 inches in length of small, green dense flowers.
Photo from Virginia
Tech Weed ID Guide
The leaves and seeds of Amaranthus palmeri are edible. The seeds are very nutritious and often ground up into flour and the leaves are cooked like spinach. There is no known poisonous member of the Amaranthus genus but when it is grown in nitrogen-rich soils (especially those with chemical fertilizers present) the leaves will have concentrated
nitrates. Eating Amaranthus palmeri is not advised if it has been grown inorganically. It has no known medical use and is sometimes used to make green and yellow dye.
Despite being edible, Amaranthus palmeri is considered to be a weed. It reduces the canopy of crops, competes in other ways, and is difficult to kill. Amaranthus p. can decrease a crop's yield and biomass by up to 50%. It invades corn, cotton, and other US grown crops, yet the presence of the crop does not decrease the productivity of the Amaranthus p. It is resistant to glycine and glyphosate herbicides and many farmers in the US have a serious problem when it invades their crops.