Swamp Sunflower

Helianthus angustifolius

Native to:
United States

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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