Collard greens are a popular leafy green vegetable, particularly in Southern United States cuisine. They belong to the Brassica family, sharing ancestry with cabbage and kale. Their appearance changes significantly from a tiny sprout to a towering mature plant, revealing the specific characteristics that define this unique, non-heading member of the cabbage relatives.
Early Growth: From Seed to Young Plant
The first visible structures after germination are the cotyledons, or seed leaves, which emerge from the soil after about five to ten days. These initial leaves are small, simple, and typically oval or kidney-bean shaped, bearing little resemblance to the mature foliage. They provide the seedling with stored energy until the true leaves can begin photosynthesis.
The appearance of the first true leaves marks the plant’s transition to independent growth. These true leaves develop from the center of the cotyledons and are the first to display the characteristic features of a collard plant, though in miniature. They are initially much smaller and may be slightly smoother than the leaves that follow.
As the plant continues to mature, these young true leaves rapidly increase in size and number, forming a small, dense cluster close to the ground. This early stage is defined by the development of a basal rosette, where the leaves grow outwards and slightly upward from a central point. This rapid leaf expansion prepares the plant for the tall, open structure it will eventually form.
The Signature Look of Mature Collard Leaves
The fully developed collard leaf is characterized by its broad, expansive surface, which can reach over a foot in length depending on the variety. These leaves are typically paddle-shaped or oval, presenting a smooth or nearly entire margin. This smooth edge is a defining visual trait that distinguishes them from heavily ruffled relatives.
The color of the mature foliage is a striking gray-green to deep blue-green, often coated in a waxy layer known as a glaucous bloom. This waxy texture helps the plant retain moisture and gives the leaves a subdued, matte appearance. The leaves are thick and notably leathery, reflecting their robust nature and ability to withstand cooler temperatures.
Running prominently through the center of each leaf is a distinct, lighter-colored main vein or midrib. This central rib extends from the base to the tip and is noticeably thicker and more fibrous than the surrounding leaf tissue. The large, flat surface, smooth margin, and thick texture create the signature visual appeal of a harvest-ready collard green.
Overall Plant Structure and Height
Collard greens are known for their upright, open growth habit as the plant matures. The leaves develop in a loose rosette around a central, progressively thickening stalk or stem. Unlike cabbage, which forms a dense, compact head, collards maintain an open structure with their leaves spreading out and up.
As the plant ages and lower leaves are harvested, the central stem elongates and becomes bare, giving the mature collard plant an almost palm-like or “tree-collard” appearance. The plant commonly grows to two to three feet tall, and some varieties may exceed this height. New leaves continuously emerge from the central growing point at the apex of the stem, allowing for a continuous, staggered harvest.
This architecture allows the plant to efficiently capture sunlight on all sides of its leaves, contributing to the dark color and robust texture of the foliage. The upright stem and loose arrangement enable good air circulation, which is beneficial for the plant’s health. The plant’s overall form is tall, leafy, and columnar, reflecting its classification as a non-heading type of Brassica.
Distinguishing Collards from Kale and Cabbage
One way to identify a collard plant is by comparing its foliage to its close relatives, kale and cabbage. The primary visual difference between collards and kale lies in the leaf margin and texture. Collard leaves are predominantly broad, flat, and have smooth edges, while kale varieties are defined by their heavily ruffled, curled, or deeply incised leaves.
Collards are sometimes mistakenly called “non-heading cabbage,” which highlights the distinction between them and true cabbage. Cabbage plants are bred to form a tight, dense, spherical head by tightly wrapping their inner leaves together. In contrast, the leaves of collard greens remain loose and open, never forming a compact ball.
While both collards and cabbage share the species name, Brassica oleracea, their growth forms are genetically distinct. The robust, upright, and open stalk of the collard plant is visually unmistakable next to the low-growing, tight sphere of a cabbage. The visual cues of a smooth, thick leaf and an open, tall stalk are the most reliable identifiers for collard greens.