Alternanthera have a rather large number of descriptive common names, including Joseph’s coat, copperleaf, calico plant, joyweed and parrot leaf, all in reference to the brightly colored leaves.
Alternanthera dentata 'Purple Knight' grows larger and stronger than A. ficoides. Given bright sun and a trellis to climb, it will grow 3 feet tall, as here. Two plants filled the end of this bed. A plant I put in shade is a pale maroon and never branched or spread.
Chartreuse alternanthera hardly grows taller than 6" and requires bright, hot sun for the best color. It does spread to the width of a large dinner plate. The red visible at right falls somewhere between the purple and the chartreuse, sometimes growing as big as a half-bushel basket in rich soil and overwhelming its chartreuse companions. It will turn red in about a month, one of the best fall color plants.