Collard greens, a biennial herb, are a horticultural variant of edible kale (cabbage). The structure and shape are very similar to that of cabbage, with the difference being that the center of the kale does not roll up into a ball. Cultivated for one year the plants form rosette-like clusters of leaves, which flower and set fruit the following year after a cold winter. Racemes are terminal, flowering from April to May, insect-mediated flowers, and the fruit is an angular, flat-orbicular fruit with round, brown seeds weighing about 4 grams per thousand grains.

Horticultural varieties of diverse forms, according to the height can be divided into high type and dwarf type; according to the shape of the leaves are divided into wrinkled leaves, non-wrinkled leaves and y cleft leaf varieties; according to the color, the edge of the leaves are emerald green, dark green, gray-green, yellowish-green, and the center of the leaves are pure white, yellowish, fleshy, rosy red, purple-red and other varieties.