Helianthus angustifolius L.

narrow-leaved sunflower (swamp sunflower)

Georgia<br>Perimeter<br>College Botanical Garden


By Thelma Glover

On a Saturday morning in October a caller on a popular call in gardening show inquired about the name of the tall yellow sunflower blooming along the roads in the Atlanta area. The host identified it as one of those native yellow sunflowers and did not venture to guess which one. At the Georgia Perimeter College Native Plant Botanical Garden we get the same question frequently during the month of October each year. The flower in question is, of course, the beautiful, showy Helianthus angustifolius, otherwise known as narrow-leaved sunflower or sometimes referred to as swamp sunflower. Just as most herbaceous flowering perennnials are closing up shop for the winter vacation, narrow-leaved sunflower makes a dramatic entrance as though it had just been waiting all year for the most appropriate time to be the center of attention It’s the only tall large-headed, yellow sunflower that blooms this late in the Atlanta area, making it so much easier to identify than all of those other DYC’s.

It can be found in the wild from Florida to Texas and northward to Missouri and New York. It is fairly common along roadsides in most counties in Georgia. The common name, swamp sunflower, insinuates that it should be found in low, moist locations-- and indeed it is. But on the other hand, it is just as likely to be found upland in dry, rocky locations. Considering this and also that the specific name, angustifolius, actually means 'narow-leaved'; maybe narrow-leaved sunflower describes it better. The genus name, Helianthus comes from the Greek, helios, sun and anthos, flower.

The seeds of sunflowers have always been a very important source of food for many song and game birds such as doves, quail, cardinals and goldfinches, as well as some mammals such as deer, moose, antelope and muskrats. Of couse, we human mammals find the seeds of the giant Helianthus annus tasty also. The Native Americans used the seeds to make meal when maize was not available. Lewis and Clark’s Journal during July, l805 mentioned Indians ... “parching sunflower seeds and then pounding them between two stones untill they were reduced to a fine meal”.

Description: Narrow-leaved sunflower is a herbaceous perennial growing from a fibrous root system with slim, short rhizomes. The stems are erect and often very branched on the upper portion surrounded by long, slender, linear (willowy) leaves that often have revolute (rolled backward) margins. The stout stems support large 2-3 inch diameter flowers that have a deep purple disc and golden yellow rays. It starts blooming in the Atlanta area by October l and lasts until the first hard frost. It is commonly confused in native plant nurseries with the much taller, Helianthus simulans, which is not native to Georgia. They are both hardy in this area , have the same cultural requirements and there is no difference from a gardening standpoint, except for the more robust habit of Helianthus simulans.