Gossypium hirsutum or Upland Cotton is an coarse annual subshrub native to Central America. In warm climates, it is biennial or perennial and will grow to 5 feet (1.5 m) tall. It has cordate leaves that are 3-5 lobed reaching up to 6 inches (15 cm) across. Cotton plants have been grown the world over for centuries as the source of cotton fibers -- fibrous trichomes copiously surrounding the seeds -- still widely used for cloth in the textile industry. Cotton is commercially grown in the Southeast United States westward to California. It is a fun plant to grow and is found in most economic plant teaching collections.
Blooming: Cotton blooms in the summer when grown outside, but when grown in the greenhouse plants can bloom at any time of the year. The white to yellowish flowers are up to 3.5 inches (8.8 cm) across. They are followed by 1.5 inch (3.9 cm) long fruits. Fruits are 3-5 celled with 5-11 seeds per cell producing copious lint and fuzz. The dehiscent capsules are well armed making it an uncomfortable plant to harvest by hand.
Culture: Gossypium hirsutum need full sun and well drained soil. In the greenhouse, we use a soil mix consisting of equal parts of loam and sand. The plants are well watered and allowed to dry slightly in between waterings and fertilized monthly during the growing and flowering season. After flowering, water is restricted even more and fertilizer is withheld until the bolls split and the cotton is harvested. At this time, the plants are destroyed and a new batch is started.
Propagation: Gossypium hirsutum is propagated from seed. Seed will germinate in 14-21 days at 68-72°F (20-23°C).
Gossypium hirsutum was featured as Plant of the Week January 13-19, 2006.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.