Tithonia rotundifolia (Mill.) S.F. Blake

CLAVEL DE MUERTO

Shrub

Perennial

Vascular

Mexican sunflower is an introduced annual in the Sunflower family (Asteraceae). It is native to Mexico and Central America, but is widely cultivated in the United States. Mexican sunflower has been collected as an escape in one Alabama county where it was abundant on the right-of-way of a county road. Mexican sunflower is a frost tender annual with a tap root. Stems are 6-11 feet in height, and sparingly branched. Leaves are alternate, petiolate, deltate in outline, and usually 3-5 lobed. The lower surface of the leaf is glabrous or short pubescent. Flowers are produced in heads. The heads are solitary on long peduncles that are hollow, flattened, and inflated just below the head. Each head has 8-13 ray flowers that range in color from red, through orange, to yellow. There are 60-90 yellow disc flowers. The fruit is a flattened achene. Mexican sunflower is a popular ornamental that thrives in poor soils and is heat and drought tolerant. It is usually available as seed. The seed can be started indoors or seeded directly in the ground after danger of frost. Plants grown in rich soils will often need to be staked to prevent them from falling over. Spent flower heads should be removed to encourage re-flowering. Mexican sunflower attracts a wide range of pollinators and is recommended as a nectar plant for Monarch butterflies.--A. Diamond

This species was first collected in Alabama by A. Diamond in 2012. He subsequently published the finding in 2014.

Not Native

Diamond, A.R. 2014. New and noteworthy vascular plant records from Alabama. Phytoneuron 2014-103: 1–10.