Swamp sunflower
Helianthus angustifolius
A tall native eastern + southeastern US perennial sunflower producing dense crowns of golden-yellow ray flowers in early to mid fall — one of the latest-blooming + most spectacular natives for fall color. Tolerates wet feet; among the best perennials for rain gardens + sunny moist meadows. Critical late-season nectar for migrating monarchs + other Lep.
Native: 24 US states
Climate fit: broad (79/100)
Pollinator
Focal point
Light
Full sun
Water
Consistent moisture
Mature size
60-96" tall · 30" apart
Hardy in zones
5a-9b
very cold to frosty winters
AHS heat range
1-11
Plant range authored in AHS heat-zone terms.
Native in Illinois
Yes
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Native across 24 US states and Canadian provinces — a wide-ranging part of North America's plant communities.
Cold hardiness
These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Well-suited
Zone 7a
Plotwright
0°F to 5°F
Well-suited
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
✓
Well-suited today and still thriving in 2050.
Heat tolerance
Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...
Where this plant fits
Suitable across 41 ecoregions — 39 climate-resilient through 2070 · 1 suited today · 1 newly possible by 2070. Best matches first.
Appalachian mixed mesophytic forests
›
Appalachian-Blue Ridge forests
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Arizona Mountains forests
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Atlantic coastal pine barrens
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Blue Mountains forests
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Canadian Aspen forests and parklands
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Central Pacific Northwest coastal forests
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Central Tallgrass prairie
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Central-Southern Cascades Forests
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Chilean Matorral
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Similar plants
Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
Rudbeckia laciniata
Cutleaf coneflower
A tall native eastern North American perennial with deeply-lobed foliage and bright-yellow drooping ray flowers around a green central cone in midsummer through fall. Spreads vigorously by rhizomes; site where colony formation is welcome. Among the most cold-tolerant native rudbeckias.
Liatris spicata
Dense blazing star
A native upright perennial of east-central NA wet meadows producing dense purple flower spikes that bloom top-down in late summer — among the most reliable monarch-migration nectar plants in the eastern flora. NC State documents goldfinches feeding on the seeds with enthusiasm, plus two specialist moth larvae (Liatris flower moth Schinia sanguinea and Liatris borer moth Carmenta anthracipennis). Native stem-nesting bees use the dead winter stems.
Vernonia noveboracensis
New York ironweed
A tall native eastern US perennial with deep purple-magenta flower clusters in late summer — among the most striking color in the native fall meadow palette. Tall and tolerant of wet feet; pairs visually with joe-pye weed + goldenrod for an iconic eastern wet-meadow trio.
Eutrochium maculatum
Spotted Joe-Pye weed
A tall native northern + central North American perennial with whorled foliage on purple-spotted stems and broad rounded clusters of mauve-pink flowers in late summer. More cold-tolerant + moisture-loving than sweet Joe-Pye weed (E. purpureum); ideal for cold-climate rain garden + wet-meadow plantings.
Eutrochium purpureum
Sweet Joe-Pye weed
A tall native perennial wildflower of moist meadows and woodland edges across eastern North America, producing large domed clusters of vanilla-scented pink-purple flowers in late summer — among the most reliable late-season nectar sources for monarchs, swallowtails, skippers, and native bees. Formerly classified as Eupatorium purpureum.
Baptisia australis
Blue false indigo
A long-lived native perennial of central and eastern US woodland borders and prairie meadows with deep blue pea-shaped flowers in late spring, blue-green leguminous foliage, attractive black seed pods for winter interest, and a nitrogen-fixing root system (Fabaceae). Larval host for 6 documented butterfly species per NC State (orange sulphur, clouded sulphur, frosted elfin, eastern tailed-blue, hoary edge, wild indigo duskywing) — among the highest Lep-host-count perennials in the eastern flora.
Appears in collections
Collection · 9 plants
Native pollinator border (eastern US)
A continuous-bloom native pollinator strip for eastern North America. Covers spring through frost with host + nectar plants spanning monarchs, native bees, hummingbirds, and specialist Lepidoptera. Little bluestem provides the matrix grass + Hesperiidae host.
Sources & citations
Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Swamp sunflower (Helianthus angustifolius). Retrieved 2026, June 24, from https://plotwright.com/plants/helianthus-angustifolius
Sources for every fact
Every fact on this page traces to a source. 18 fields cited - 18 source-backed.
NC State Extension Gardener Plant Toolbox
University extension service
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
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Regional guidance
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Designer notes