Swamp Sunflower
Helianthus angustifolius
- Native to:
- United States
sonnia hill






Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Helianthus
- Species:
- Helianthus angustifolius
- USDA Symbol:
- HEAN2
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 200 cm
- Light Requirements:
- Part Shade
- Drought Tolerance:
- Medium
- Bloom Months:
- sep,oct,nov
- Bloom Colors:
- yellow
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
- Pollen Specialist Bee Keystone:
- ★★★★★ Native pollen specialist bee species supported by this genus (NWF)
Host Plant for Caterpillars
false prominent (Schizura leptinoides)
Reported Fauna Sightings
Bees: American bumble (Bombus pensylvanicus), Common eastern (Bombus impatiens) Moths:Yellow Stiria (Stiria rugifrons) Butterflies:Atalopedes Scudder, ⚠️Monarch butterfly (Danaus plexippus)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, birds, small mammals
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts vigorously from rhizomes after fire. Benefits from periodic burning to reduce competition.
Soil Requirements
- Soil Type:
- moist, sandy, well-drained soil
- pH:
- 5.5 - 6.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- prefers wetland margins and moist prairies
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 7–21 days
- Notes:
- Seeds germinate readily after cold stratification. Light may improve germination rates.
The above propagation data sourced from Claude AI
Pre-treatment: Single-step cold-moist stratification for temperate woodland species. for 60–120 days
Source: Claude AI