Helianthus angustifolius

Foliage: The leaves are narrow, lance-shaped, and dark green, giving the plant a graceful appearance.

Flowers: Produces bright yellow, daisy-like flowers with dark centers from late summer to fall. The flowers are around 2-3 inches in diameter and attract pollinators such as bees and butterflies.

Light Requirements: Thrives in full sun. Plant in a location that receives at least 6-8 hours of direct sunlight each day for optimal growth and flowering. This plant can tolerate partial shade but will produce fewer flowers.

Soil Requirements: Prefers well-draining, moist soil. Helianthus angustifolius is highly adaptable to various soil types, including sandy, loamy, and clay soils. It thrives in slightly acidic to neutral pH levels, ideally between 5.5 and 7.5. This plant is particularly suited for wet conditions, making it an excellent choice for rain gardens, pond edges, and other areas that experience occasional flooding.

Watering: Requires regular watering, especially during dry periods. Swamp Sunflower prefers consistently moist soil and can tolerate wet conditions. While it can handle brief drought periods once established, maintaining soil moisture is essential for its overall health and flower production. Mulching around the plant can help conserve moisture.

Temperature and Humidity: Hardy in USDA zones 6-9. Helianthus angustifolius is well-suited to warm, humid climates typical of its native range in the southeastern United States. It tolerates a range of humidity levels and can withstand heat well. In cooler climates, it can still thrive but may have a shorter blooming period.

Fertilization: Typically does not require much fertilization if planted in nutrient-rich soil. However, applying a balanced, slow-release fertilizer in early spring can support vigorous growth and flowering. Over-fertilization should be avoided, as it can lead to excessive foliage growth at the expense of flowers.

Pruning: Deadhead spent flowers to encourage prolonged blooming and prevent self-seeding if desired. Cutting the plant back by one-third after the initial bloom can promote a second flowering period and help maintain a neat appearance. In late fall or early winter, cut the plant back to the ground after the foliage has died back.

Pests and Problems: Generally pest-resistant, but may occasionally attract aphids, spider mites, or caterpillars. Ensure good air circulation to prevent fungal diseases such as powdery mildew or rust. If pests or diseases appear, treat with insecticidal soap or neem oil. Regular inspections can help catch any issues early.