The Brussels sprout plant, scientifically known as Brassica oleracea Gemmifera Group, belongs to the large family of cruciferous vegetables that includes cabbage, kale, and broccoli. Most people only encounter the small, edible buds in the store, which are a fraction of the full-grown plant’s size. The entire plant stands as a tall, leafy stalk. It is a cool-season biennial, though it is typically cultivated as an annual crop for its harvestable buds.
Overall Plant Dimensions and Stalk
The mature Brussels sprout plant is a towering structure, often reaching a height of 2 to 4 feet (60 to 120 centimeters), depending on the specific variety and growing conditions. This height makes the plant look surprisingly large compared to the small, one-inch sprouts it is known for. The central support is a single, thick, rigid stalk, which is typically grayish-green in color.
The stalk’s woody texture and upright habit give the plant a columnar appearance, sometimes resembling a small, slender palm tree. This resemblance is particularly noticeable toward the end of the growing season after the lower leaves have been removed or have naturally yellowed and dropped off. This strong central stem is necessary to support the significant weight of the dense foliage and the dozens of tightly-formed sprouts it will eventually bear.
Leaf Structure and Coloration
The foliage of the Brussels sprout plant is a prominent feature, contrasting sharply with the thick central stalk. The leaves are large, simple, and grow alternately up the stem, reaching lengths of up to 12 inches. They are generally broad and somewhat paddle-shaped, resembling the leaves of collard greens or cabbage, which is unsurprising since they share the same species.
A distinguishing characteristic of the leaves is their waxy coating, which gives them a slightly glaucous appearance. This natural coating creates a muted blue-green or gray-green coloration that can sometimes appear almost dusty. The leaves extend outward and upward from the main stalk, collecting the necessary sunlight to fuel the growth of the developing buds. These large leaves are also edible and are sometimes harvested and cooked like other hardy greens.
The Unique Growth Habit of the Sprouts
The edible Brussels sprout is not a fruit or flower, but is actually a lateral bud, also known as an axillary bud. These buds form in the leaf axil, the specific point where the petiole, or leaf stalk, meets the main stem. This placement results in the sprouts growing in a dense, spiral pattern all the way up the main stalk.
Each sprout develops into a miniature, tightly packed head, structurally identical to a tiny cabbage. The sprouts typically measure between 1 to 2 inches in diameter when they are ready for harvest. The maturation process is sequential, beginning with the lowest buds on the stalk and gradually progressing toward the top. This pattern means the bottom sprouts are ready to be picked weeks before the buds near the plant’s apex have fully tightened.