Rayless Sunflower (Helianthus radula)

Educational Story

Rayless Sunflower, Helianthus radula, is a sunflower that produces a tight cluster of purple to brown, tighly packed disk flowers atop a long stalk.  This sunflower lacks the showy, outer ray flowers of the inflorescence typical of other members of the Asteraceae, like daisies.  It has large, rounded, hairy basal leaves growing close to the ground.  The native range of this species is the southern coastal plain from South Carolina to Louisiana and Florida.  It thrives in wet, sunny locations and is a great wildflower to use in native plantings and pollinator gardens.

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Gardening Facts

Scientific Name: Helianthus radula
Common Name: Rayless Sunflower, Stiff Sunflower
Description of facts and concepts: Long stalk with a dark purple compact flower head. Often thought to be a dead flower since it doesn’t display the typical ray flowers around the disk as in other members of the Asteraceae.
Seed or division information: Seeds fall due to gravity
Date of flower’s bloom (Month and week): Summer, fall
Ecoregion: Pinelands
Color of Flower: Dark Red to purple
Height: 3 feet and up
Spread: 1-3 feet
Family: Asteraceae (aster or daisy)
Soil Type: Base to Acidic Acidic
Soil: Dry to Wet Moist
Light: Sun to Shade Sun
Zone 8A-9B