Aster Family (Asteraceae / Compositae)
Several species of sunflower are found in North America. The large annual sunflower Heleanthus annuus is thought to have originated in the Western U.S. and developed by Native Americans from the smaller many branched native sunflower.
Many cultivars have been produced with flower colors ranging from yellow through dark brown.Be aware that some pollenless cultivars have been produced. Also, some varieties can produce seed without insect pollinators.
Cultivars can grow up to 17 feet in height with blooms up to 12 inches wide. Sunflowers have both ray (“petals”) and disc flowers on a single flower head that bloom from summer to fall. The central disk flowers produce the seed.
Sun flowers do best on well drained fertile soils in full sun but will grow on poor disturbed soils. They may require an occasional deep watering depending on how dry the climate is. Taller types may tip over in windy conditions.
- Caterpillar of the Gorgone checkerspot butterfly (Charidryas gorgone)
- Caterpillar of the Painted Lady butterfly (Vanessa cardui)
- Edible seeds attract birds