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(updated January 21, 2021)

Prairie Sunflower

Helianthus petiolaris Nutt.

Asteraceae (Sunflower Family)

▲▼ young plants

▲▼ young plants 

 

▲ ▼ mature flowering plants 

▲ ▼ mature flowering plants

 

leaves and flower buds ▲

▲flower closer view

 

Helianthus petiolaris Nutt., Prairie Sunflower:  (Bayer Code:  HELPE; US Code HEPE)

·         U.S. native summer annual, 1-4 feet tall, with green to brownish-purple stems; stems are rough-hairy, and plants branch from the base

·         Leaves are opposite, triangular to lanceolate, rough-textured, with long petioles; leaves have a few teeth or smooth margins; three main leaf veins arise from the petiole

·         Head inflorescences are 1.5-3 inches across, with 10-30 ray florets (“petals”) that are puckered where they join the head, and center of 50-100 reddish-brown disk florets

·         Stalks supporting the heads (peduncles) can be up to 16 inches long

·         Bracts below the inflorescence are in several rows, lanceolate with elongated pointed tips, rough-textured, with hairs on margins; bracts stand out from the base of the inflorescence

·         Flowering from mid-summer to mid-autumn

·         Found in cultivated fields, right-of-ways, prairies, pastures; more common in disturbed sites; tolerant of sandy soils; more common in western plains states

·         Appears quite similar to Annual Sunflower (Helianthus annuus), except annual sunflower has larger flowers and leaves, leaves are more broad, and flower stalks (peduncles) tend to be shorter

 

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