Tithonia diversifolia (ASTERACEAE) Japanese Sunflower

Weeds to Whack

Japanese Sunflower is not a native of Japan or anywhere near it. In fact, it is a native of Central America. It is a tall robust annual herb with erect stems forming bushes to 3 m high. Common along roadsides, creeks, embankments and neglected suburban lots. Leaves are hairy with 3 or 5 pointed lobes and a wedge-shaped base, scalloped (crenated).
Photo: Robert Whyte

Flower and Buds

Flower heads resemble sunflowers with 4-5 cm long yellow petals and a yellow central disc in small groups at the ends of leafy branches. Flowers in spring to autumn. Seeds are hairy, with a ring of scales and two spines. A similar species, Mexican sunflower Tithonia rotundifolia, has leaves that are entire or with rounded leaf lobes and its petals are orange on the upper surface and yellow underneath.

Photo: Mark Crocker