The cotton plant is a globally cultivated crop prized for the fiber that surrounds its seeds. Although botanically a perennial shrub, it is typically grown commercially as a warm-season annual plant. The physical appearance of the plant changes dramatically as it progresses from a simple green shrub to one covered in fluffy white fiber.
Vegetative Stage: Leaves, Stems, and Overall Growth
The initial growth period focuses on building the plant’s structure. During this stage, the cotton plant resembles a leafy, bushy shrub, typically reaching a height of one to two meters in commercial fields. The main stem grows upright, displaying nodes where leaves and branches emerge in an alternate, spiral pattern. Stems are green, sometimes possessing a reddish tint depending on the variety and maturity.
The most recognizable feature of the young plant is its broad, palmate foliage. These true leaves usually have three to five lobes, though some cultivated varieties have deeply cut, “okra-leaf” shapes. The green leaves convert sunlight into the carbohydrates needed for rapid growth. Below the surface, the plant develops a taproot system that can grow rapidly, sometimes reaching depths twice the height of the young plant.
Reproductive Stage: The Flowers and Green Bolls
The plant transitions to its reproductive phase with the appearance of “squares.” These are small, triangular flower buds enclosed by three protective leaf-like structures called bracts. After developing for about three weeks, the square opens into a hibiscus-like flower, which is creamy white or pale yellow when it first blooms.
The cotton flower is short-lived, changing color soon after successful pollination. Within 24 to 48 hours, the petals darken, turning pink, red, or fuchsia. This color change signals fertilization; the flower then withers and drops off, leaving behind the newly forming fruit. This developing fruit is called a boll, a hard, protective capsule that is initially dark green and segmented. These young bolls contain the immature seeds and the nascent cotton fibers.
Maturity and Harvest: Appearance of the Fiber
As the cotton boll matures, it reaches full size about 25 days after the flower drops. During the next several weeks, the fibers inside elongate and thicken.
The most recognizable transformation occurs when the boll ripens and begins to dry out. The hard green casing, known as the bur, naturally cracks open along its segments, a process called dehiscence. As the bur pulls back and dries to a brown color, it reveals the fluffy white contents inside. This is the mature cotton fiber, or lint, a soft, tangled collection of fibers attached to the seeds. The open boll structure, contrasting the brown, dried bur and bright white fiber, is the appearance associated with a field ready for harvest.