Approximately 50 seeds per packet
Collected: 2024
Packaged: 2025
Germination code: C30
Please refer to our germination codes and growing information for recommendations and tips.
Seed treatment recommended: this species requires a minimum of 30 days of cold moist stratification to break its natural dormancy and encourage germination. Alternatively, sow seeds in outdoor containers in the fall or winter, with germination occuring in the spring.
Seeds of this species appreciate being covered by a thin layer of soil or buried when sown to aid in germination. A general rule of thumb is to cover them with a layer of soil no more than two to three times their width. However, it's better to plant seeds shallow, and most seeds will germinate even if surface sown. (Optional) Sprinkling a layer of sterile sand or vermiculite overtop the soil and sown seeds usually won't negatively impact germination, and may help to maintain soil moisture and deter mold.
Helianthus angustifolius (Narrowleaf sunflower) Seed Packet
Maryland and Virginia ecotypes
Name: Helianthus angustifolius (Narrowleaf sunflower)
Habit: upright, arching, naturalizing
Size: 3 – 8 ft. tall, half as wide
Flowering time: Sep, Oct, Nov
Bloom color: Yellow
Habitat: Floodplains, moist open woods, bogs, coastal saltmarshes
Moisture: Average to wet, poor to well draining
Light: Full sun, part sun
Soils: Clay, loamy, sandy
Uses: pollinator gardens, cottage gardens, lakes/ponds, rain gardensNarrowleaf sunflower, also called swamp sunflower, is a species that thrives in wet habitats such as marshes, swamps, wet meadows, and roadside ditches, where it can form dense stands. This tall, vigorous plant can reach heights of 5 to 8 feet, with slender, lance-shaped leaves on long stalks.
This sunflower releases a profusion of bright yellow, daisy-like flowers that bloom in late summer to fall. Each flower head consists of golden-yellow ray florets encircling a darker brown to purple central disk, providing a vibrant flash of color when most summer blooms have winded down. It serves as an important late-season nectar source for pollinators, including many native bees, moths and butterflies. Additionally, its abundant seeds provide a valuable food source for birds, particularly finches.
Due to its adaptability, it can tolerate a range of soil types, though it prefers moist, well-drained soils and full sun. It is drought-tolerant once established and can be used effectively for erosion control in wetland restoration projects.
Helianthus is considered a keystone species for supporting native wildlife, and is a host plant for many species of butterfly and moth. This genus also supports several rare and uncommon pollen specialist bees, which can only feed on the pollen of a select few flowers to survive.