Family: Malvaceae
Common Name: Cotton

These shrubs are found in warmer regions of the world, one species being the cotton pro­duced commercially for cotton and cotton seed oil. The leaves have spotted oil glands, and the open flowers are like small hibiscus and coloured from white to yellow to purplish red, often spotted purplish red towards the base. The seeds are usually covered with down or loose lint.

Species

G. arboreum, tree cotton, to 4 m (13 ft), is widely cultivated in Asia. The flowers are yellow with a purplish red base.

G. bar­badense, sea island cotton, to 3 m (10 ft), has yellowish purple flowers. Var. brasiliense, kidney cotton, has larger flowers and fruit cap­sules.

G. herbaceum, Levant cotton, is a hairy annual or perennial, to 2 m (6 ft), with yellow­ish purple flowers.

G. hirsutum, upland cotton, is a shrub, to 2 m (6 ft), with creamish yellow flowers, turning purple with maturity.

G. stur­tianum, Sturt's desert rose, is the floral emblem of the Northern Territory in Australia. This Australian native is an erect or rounded shrub, to 2 m (6 ft), with mauve, red-centered, summer flowers.

G. thurberi, wild cotton, is a shrub to 4 m (13 ft), with lobed leaves and whitish yellow flowers, purple on the under-sides.

Cultivation

In frost-prone climates, grow cotton for its novelty value in a cool to intermediate greenhouse or conservatory. Cotton needs humid conditions and abundant moisture during the growing season, and prefers a com­post of loam and peat. Propagate from seed sown in spring at a temperature no lower than 16°C (61°F). Small plants can be potted on as required during summer. Commercial cotton must be harvested during dry weather.

Climate

Zone 10, but grown as a summer annual.