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Smooth sunflower

Helianthus laevigatus

Smooth sunflower
Photo: Unknown author, CC0

Smooth sunflower is a tall, rhizome-spreading perennial native to the eastern and southeastern United States, growing in open, sunny habitats. It is grown in gardens for its late-season yellow daisy-like blooms and tolerates a range of conditions.

Family
Asteraceae (Daisy family)
Grows as
Perennial
Light
Full sun
Water
Water deeply during dry spells while established; it tolerates some drought once settled.
Soil
Average to moderately rich, well-drained garden soil; tolerates clay and shale-derived soils.
Temperature
Hardy in cold winters (roughly USDA zones 5-9); mature plants tolerate heat and frost well.
How easy
Easy
Native range
West Virginia to South Carolina

About

Helianthus laevigatus is a North American species of sunflower known by the common name smooth sunflower. It is native to the east-central and southeastern United States from Georgia to Maryland.

Helianthus laevigatus is a perennial herb up to 220 cm (over 7 feet) tall, spreading by means of underground rhizomes. Most of the leaves are on the stem rather than crowded around the base, each leaf up to 15 cm (6 inches) long. Leaves and stems generally have no hairs, and the undersides of the leaves sometimes appear pale because of a layer of wax on the surface. One plant usually produces 1-6 flower heads. Each head has 5-10 yellow ray florets surrounding 40 or more yellow disc florets. The plant grows on soils derived from shale.

Other Helianthus plants

Southeastern sunflower · Helianthus ambiguus · Swamp sunflower · Common sunflower · Western sunflower · Silverleaf sunflower · Arizona sunflower · Purpledisk sunflower · Serpentine sunflower · Helianthus brevifolius · California sunflower · Lakeside sunflower

Text excerpted from the Wikipedia article Helianthus laevigatus by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.

The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.

Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.

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