H. a. ssp. Summer annual with coarse foliage and showy yellow flowers, to 3 m tall.
Plants are highly variable wild forms of the cultivated sunflower.
Erect herbaceous perennial , to 0.7 m tall, with bluish-green foliage and creeping roots . New shoots from root buds often create dense patches of plants. Introduced from south central U.S. and northern Mexico. First few true leaves opposite, dull green, covered with short bristly hairs that are rough to touch. Margins weakly round-toothed.