Swamp Sunflower (Helianthus angustifolius)

Swamp Sunflower (Helianthus angustifolius)

Swamp Sunflower is the bayou garden's autumn grand finale — a towering native sunflower that waits patiently through the entire growing season, then erupts in October in a spectacular display of hundreds of golden-yellow flowers that transforms the garden into a sea of sunshine just as everything else is winding down. It is one of the most dramatic native wildflowers in the South, and in Louisiana, it is perfectly timed to fuel the last monarchs of the season as they pass through on their way to Mexico.

Botanical Profile

• Family: Asteraceae (Daisy family)
• Native Range: Eastern United States from New York to Florida and west to Texas; native to Louisiana's wet prairies, bayou edges, and moist open areas
• USDA Hardiness Zones: 5–10
• Mature Size: 5–8 feet tall; spreads by rhizome to form colonies
• Bloom Time: September–November (one of the latest-blooming native wildflowers)
• Sun: Full sun
• Soil: Moist to wet; tolerates clay and periodic flooding; thrives along bayou edges and in rain gardens

Ecological Role

Swamp Sunflower's late-season bloom makes it one of the most ecologically critical native wildflowers in the South — providing abundant nectar for migrating monarchs, painted ladies, and cloudless sulphurs in October and November when almost nothing else is blooming. It supports specialist sunflower bees (Melissodes and Svastra species) and its seeds feed American Goldfinches, Purple Finches, and sparrows through fall and winter. Its rhizomatous spread creates dense colonies that stabilize moist stream banks and provide wildlife cover.

In the Living Canopy & Understory

Part of the Jardin — The Living Canopy & Understory collection at Big Mamou Enterprises, Swamp Sunflower is the bayou garden's golden October finale — tall, spectacular, and sending the last monarchs of the year south in a blaze of sunshine.