Helianthus Divaricatus

As I write this, winter storms are threatening parts of the Great Lakes region, with snow and freezing rain forecast. So to help us escape for a moment from the impending winter, I thought this month’s native plant of the month should be the quintessential summer blossom. And what could be more summery than a Sunflower? Woodland Sunflowers will thrive in full sun to part shade and promise to brighten your garden for much of the summer and into the fall. 

Common Name: Woodland Sunflower 

Scientific Name: Helianthus divaricatus 

Family: Asteraceae (Aster Family) 

Alternate Common Names: Rough Sunflower, Rough Woodland Sunflower 

Plant description: Woodland Sunflower has rigid, upright stems that are unbranched except for where flowers occur. These stems are light green to dark purple and smooth or sparsely covered in short, stiff hairs. Alternate leaves are attached directly to the stem in an opposite pattern and are rotated 90 degrees horizontally from the leaves below them. Leaves are lance-shaped to ovate with a rounded base, pointed tip and measure up to 15cm long and 5cm across. Leaf margins may be toothless or have widely spaced teeth. Stems terminate with 2.5-7.5cm wide flowers borne on slender stalks. Each flower is characterized by 8-15 bright yellow, widely spreading ray florets (petals) surrounding a slightly darker center disk. Flowers are replaced by globular seed heads containing numerous black seeds. 

In the Garden: The radiant yellow flowers of Woodland Sunflower bloom in profusion and lighten up partly shaded areas of the garden. Its adaptability and long bloom time mean it will quickly become a favourite in your garden. The flowers fade to globular seed heads that persist well into the winter months to extend seasonal interest and wildlife value. 

Lifespan: perennial 

Exposure: sun, part shade 

Soil Type: sandy, loamy or rocky 

Moisture: moist to dry 

Height:  30-180 cm 

Spread: 30-90 cm 

Bloom Period: Jun, Jul, Aug, Sep 

Colour: yellow 

Fragrant (Y/N):

Showy Fruit (Y/N):

Cut Flower (Y/N):

Pests: no serious insect or disease problems 

Natural Habitat: dry, open woodland or savanna 

Wildlife value: the nectar and pollen of the flowers attract a wide variety of insects and native bees, and the seeds are eaten by many small birds, squirrels and mice 

Butterfly Larva Host Plant For: Silvery Checkerspot (Chlosyne nycteis) and Gorgone Checkerspot (C. gorgone), and Painted Lady (Vanessa cardui

USDA Hardiness Zone: 3-8 

Propagation: Seeds direct sown in the fall will germinate in the spring. If starting the seeds in doors, requires 30 days cold moist stratification. Divide every 3-4 years to control spread and maintain vigor. 

The small sunflower seeds look very much like the larger ones we’re used to seeing in our birdseed. (Image source Prairie Moon Nursery)

Additional Info: Spreads over time by creeping rhizomes to form colonies. Woodland Sunflower is a vigorous spreader and therefore may not be suitable for small planting areas. 

Native Range: 

Shaded area indicates the pre-European native range of Helianthus divaricatus.