HELIANTHUS angustifolius (Swamp Sunflower) is a perennial flowering plant native to the eastern and southeastern regions of the United States. It is a member of the Asteraceae family and is known for its tall stature, bright yellow flowers, and ability to thrive in wet or swampy conditions.
Swamp Sunflower is a tall perennial that typically grows to a height of 3 to 8 feet (0.9 to 2.4 meters) and spreads about 2 to 4 feet (0.6 to 1.2 meters) wide. It has slender, erect stems and narrow, lance-shaped leaves. The leaves are typically long and have a rough texture. The plant produces numerous flower heads in branching clusters at the top of each stem.
The flowers of Swamp Sunflower are the main attraction. Each flower head consists of a dark brown center, known as the disc florets, surrounded by bright yellow ray florets. The ray florets are typically numerous and slightly drooping, creating a radiant display. The flower heads are relatively small compared to some sunflower species, reaching up to 2 inches (5 cm) in diameter.
Swamp Sunflower typically blooms from late summer to fall, depending on the specific growing conditions and climate. The flowering period can last several weeks, providing a burst of late-season color and attracting pollinators to the garden. The bright flowers of Swamp Sunflower are highly attractive to pollinators, including bees, butterflies, and other beneficial insects. They provide a valuable late-season nectar source when other flowers may be scarce. Additionally, the seeds produced by the plant are highly favored by birds, making Swamp Sunflower a valuable addition to wildlife gardens.
Helianthus angustifolius thrives in full sun to partial shade and moist to wet soil conditions. It is specifically adapted to swampy or poorly drained areas, making it an ideal choice for rain gardens or wetland habitats. While it prefers moist conditions, it can tolerate short periods of drought once established. Swamp Sunflower is a hardy plant and can even withstand occasional flooding.
Swamp Sunflower is generally low-maintenance. Deadheading spent flowers can help promote prolonged blooming and prevent self-seeding if desired. However, allowing some seed heads to mature can provide food for birds and contribute to the natural reseeding of the plant. The tall stems may benefit from staking to prevent them from bending or breaking under windy conditions.
Helianthus angustifolius can be grown from seeds or propagated through division. Sow the seeds directly into the garden soil in early spring or late fall, or divide mature clumps in early spring. Provide adequate spacing between plants to accommodate their size. Swamp Sunflower is often grown in rain gardens, wetland restorations, or naturalized areas where it can thrive in moist to wet conditions.
Swamp Sunflower (Helianthus angustifolius) is a striking perennial plant that brings late-season beauty and wildlife attraction to gardens and landscapes. With its tall stature, bright yellow flowers, and adaptability to wet or swampy conditions, it is a valuable addition for attracting pollinators, supporting biodiversity, and creating habitat in waterlogged areas. Whether grown for its ornamental value or to enhance wetland habitats, Swamp Sunflower can make a beautiful and ecological statement in the garden.
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