< BACK

Helianthus angustifolius

Asteraceae

Swamp sunflower or narrowleaf sunflower (Helianthus angustifolius) is one of the most common and recognized fall wildflowers. It is a native herbaceous perennial in the sunflower family (Asteraceae). The flowers have five petals and five stamens, and the pappus is comprised of two deciduous, awn-like scales. The ray flowers are sterile and yellow. The disc flowers are perfect and red or brown. The ovary is inferior, and the fruit is an achene. The leaves are alternate or opposite, simple, with pinnate major veins and long and narrow with margins inrolled (a picture from June of the leaves is attached). It is a perennial but does not compete with other native perennials and soon disappears if an area is not re disturbed. That is why it is so common along roadsides but not in mature forests. Johnny (don’t be shy) Mayronne selected a cultivar “Mellow Yellow” of this species (shout out to Johnny). This species is abundant in some areas on Allen Acres but completely absent in other areas. I am a long way from a swamp and often wonder about the swamp sunflower name. Several moth species are reported to eat the leaves of the genus Helianthus and one (black-blotched Schizura-Schizura leptinoides) is reported to eat this species.