Swamp sunflower is a native, herbaceous perennial member of the daisy family (Asteraceae) and can be found from NY to FL to TX. The species epithet is compounded from the Latin and means “narrow-leaved.” It prefers moist to occasionally wet acidic sandy to clay loams in full sun. It can be grown on drier soils if adequate moisture is provided. It will tolerate part shade but flowers better in full sun. It is a large perennial that can grow up to 8 feet tall with showy yellow daisy-like flowers from mid to late summer into fall. Prune plants back in June to encourage branching. This plant is a favorite of pollinators and songbirds. Because stems can be flimsy, plants may need to be staked, especially if planted in a windy location. There are shorter cultivars available if desired. It is sometimes treated as an annual in colder climates. Use this plant in the back border of a native/pollinator garden, naturalized area, or along streams and ponds. It works well in pollinator and butterfly gardens, as well as rain gardens. Give it room to grow and spread (which it does aggressively), and you will have a profusion of late-season flowers when little else is blooming. This plant was selected as the 2007 NC Wildflower of the Year , a program managed by the North Carolina Botanical Garden with some financial support from the Garden Club of North Carolina. Insects, Diseases and Other Plant Problems: Caterpillars and beetles often chew on the foliage but seldom cause enough damage to warrant management. Rust, leaf fungal spots and powdery mildew are somewhat common. More information on Helianthus .
Source: NC State Extension Gardener Plant Toolbox ↗Reconciled to full toolbox: matched by slug to slug 'helianthus-angustifolius'. Identity (id/common/scientific name) preserved from the original 87-plant Hunnicutt set; attribute data refreshed from the 65-attribute toolbox scrape.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Also noted by NC State
Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell
apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand
Soil pH
Acid (<6.0)
Soil drainage
Good Drainage | Moist | Occasionally Wet
Available space
12 inches-3 feet; 3 feet-6 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 5 ft. 0 in. - 8 ft. 0 in. | Width: 2 ft. 6 in. - 4 ft. 0 in.
Growth rate
Medium
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Erect
Texture
Medium
Foliage
Deciduous
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Linear
Leaf margin
Entire
Leaf feel
Rough
Leaf size
> 6 inches long, < 1 inch wide
Hairs present
Yes
Leaf detail
Leaves are narrow, willowy, scratchy, simple, hairy and pointed at the tip. The leaves have three linear veins.
Flower color
Gold/Yellow
Flower value
Showy
Flower form
Head
Flower shape
Radial
Flower size
1-3 inches
Flower detail
A profusion of 2-to-3-inch "flowers" (inflorescences) with 10 to 20 yellow, narrow, pointed rays surrounds a purplish-brown disk. Has hairy bracts. Blooms in late summer into fall (July-frost).
Bloom time
Fall; Summer
Fruit type
Achene
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
Displays from September to November
Stem color
Green; Purple/Lavender
Stem detail
Green to purplish pubescent stems
Wildlife & Ecology
Native status
Native
Origin
USA
Distribution
AL , AR , DC , DE , FL , GA , IL , IN , KY , LA , MD , MO , MS , NC , NJ , NY , OH , OK , PA , SC , TN , TX , VA , WV
Wildlife value
Flowers provide nectar to pollinators from July until the first frost. This is a larval host plant that supports Silvery Checkerspot (Chlosyne nycteis). The Silvery Checkerspot has 1 or 2 broods in the north from June-July in the deep south and Texas, they have as many as 3 or 4 broods from May through September. Songbirds, ruffed grouse, quail, mourning doves, and small mammals are attracted to seeds, so leave standing dead flowers into the winter as natural bird feeders. Members of the genus Helianthus support the following specialized bees: Andrena (Callandrena s.l.) accepta, Andrena (Callandrena s.l.) aliciae, Andrena (Callandrena s.l.) helianthi, Melissodes (Eumelissodes) agilis, Dieunomia (Dieunomia) heteropoda, Megachile (Sayapis) pugnata, and Paranthidium (Paranthidium) jugatorium.