Saturday, September 19, 2015
Variable-leaved Sunflower - Helianthus heterophyllus
Many of our native sunflowers can be tricky to differentiate by species. Variable-leaved sunflower is most easily identified by its relative lack of leaves along the stem. It produces a tuft of 4-6" long linear leaves in spring, They are rough to the touch - a result of the many stiff hairs along the surface and leaf edge. Though a few of these leaves may occur a short distance up the 4-5 foot tall hairy stem, it is mostly leafless. A single flower head is produced at the top of each by mid-summer.
The composite flowers are comprised of 1-2 dozen bright yellow ray petals surrounding a dark center of disk flowers. The size of these flower heads is variable, but can be 4 inches across. Like other sunflowers, they are exceptional at attracting pollinating insects and the ripened seeds provide food for various seed-eating birds.
Variable-leaved sunflower is not propagated by any of the native nurseries in Florida associated with FANN - the Florida Association of Native Nurseries, though other species are commonly offered. It would require sunny moist locations to prosper and it would require ample space as it has a tendency to spread by underground rhizomes.