The artichoke is known for its layered appearance. Many people are surprised to learn that the part they eat is not a root or a leaf, but rather the unopened flower of a large plant. Understanding how its flower develops reveals why the artichoke is harvested and prepared in a unique way. The final edible globe represents a tightly packed cluster of future blooms, picked just before they transform into something inedible.
The Artichoke Plant Structure
Artichokes are grown on a species of thistle, which is a member of the daisy family Asteraceae. The globe artichoke is a cultivated variety known botanically as Cynara cardunculus var. scolymus. This perennial plant establishes itself over several seasons.
The plant grows in an upright clump, reaching heights and widths of up to six feet at maturity. From the central crown sprouts a rosette of deeply lobed leaves that can be three feet long. These leaves are silvery-green, covered in fine hairs that give them a slightly glaucous, or waxy, appearance.
A central stalk emerges from the center of the rosette, bearing the edible buds. Artichokes are herbaceous perennials; their top growth dies back in colder months but their root system survives to re-sprout the following spring. The plant’s deep roots allow it to support the flower heads that develop high above the foliage.
Development and Harvesting of the Edible Bud
The edible artichoke is an immature inflorescence, or flower head, that forms at the top of the stalk. This globe is composed of numerous triangular scales, which are actually fleshy protective leaves called bracts. These bracts surround the center known as the heart, which is the receptacle of the flower.
Bud formation begins with the terminal bud at the tip of the main stalk. After this primary bud is established, smaller, secondary buds develop lower down the stem. This staggered growth allows for several harvesting passes from a single plant throughout the growing season.
Harvesting occurs when the bud is firm to the touch and still tightly closed. Harvesting before the bud matures is necessary because if left too long, the bracts begin to pull away from the center. This stretching indicates that the immature flower parts inside are starting to harden and become fibrous. If the bud is not picked, it will open into a large purple flower that is inedible. This transformation also causes the center known as the choke to become tough and prickly. The primary harvesting window occurs in the late spring, with a second crop of smaller buds often maturing in the late summer or early fall.