I've tried it for the last two years - it's hard to get a sunflower to grow before the birds eat the seeds! I've been woefully unsuccessful - so I probably won't participate this year.
Linda T in Atlanta, sunflowerless
USA has many sunflower species and some are perennial. Some flower long time if you take developing seeds away.
Helianthemun rigidus continues flowering several weeks if you take old flowers off and pertilize it.
Once I reared Helianthus anomalus because it makes flowers more and more in branches. But no bees or bumblebees or butterflyes visited there.
Species
Helianthus agrestis : Southeastern Sunflower
Helianthus angustifolius : Swamp Sunflower
Helianthus annuus : Common Sunflower, Girasol (Spanish)
Helianthus anomalus : Western Sunflower
Helianthus argophyllus : Silverleaf Sunflower
Helianthus arizonensis : Arizona Sunflower
Helianthus atrorubens
Helianthus bolanderi : Serpentine Sunflower
Helianthus californicus : California Sunflower
Helianthus carnosus : Lakeside Sunflower
Helianthus ciliaris : Texas Blueweed
Helianthus cinereus
Helianthus couplandii : Prairie Sunflower
Helianthus cusickii : Cusick's Sunflower
Prairie Sunflower (Helianthus petiolaris)Helianthus debilis : Cucumberleaf Sunflower
Helianthus debilis ssp. cucumerifolius : Cucumberleaf Sunflower
Helianthus debelis ssp. debilis : Beach Sunflower, Dune Sunflower
Helianthus debilis ssp. silvestris : Cucumberleaf Sunflower
Helianthus debilis ssp. tardiflorus : Cucumberleaf Sunflower
Helianthus debilis ssp. vestitus : Cucumberleaf Sunflower
Helianthus decapetalus : Thinleaf Sunflower
Helianthus deserticola
Helianthus divaricatus : Woodland Sunflower
Helianthus eggertii : Eggert's Sunflower
Helianthus floridanus : Florida Sunflower
Helianthus giganteus
Helianthus glaucophyllus : Whiteleaf Sunflower
Helianthus gracilentus : Slender Sunflower
Helianthus grosseserratus: Sawtooth Sunflower
Helianthus heterophyllus : Variableleaf Sunflower
Helianthus hirsutus
Helianthus laciniatus : Alkali Sunflower
Helianthus laetiflorus
Helianthus laevigatus : Smooth Sunflower
Helianthus longifolius : Longleaf Sunflower
Willowleaf Sunflower (Helianthus salicifolius)Helianthus maximiliani : Maximillian Sunflower
Helianthus microcephalus : Small Woodland Sunflower
Helianthus mollis : Downy Sunflower, Ashy Sunflower
Helianthus multiflorus
Helianthus neglectus : Neglected Sunflower
Helianthus niveus
Helianthus niveus ssp. canescens : Showy Sunflower
Helianthus niveus ssp. tephrodes : Algodones Sunflower
Helianthus nuttallii
Helianthus nuttallii ssp. nuttallii : Nuttall's Sunflower
Helianthus nuttallii ssp. parishii : Parish's Sunflower
Helianthus nuttallii ssp. Rydbergii : Rydberg's Sunflower
Helianthus occidentalis : Fewleaf Sunflower
Helianthus occidentalis ssp. occidentalis : Fewleaf Sunflower
Helianthus occidentalis ssp. plantagineus : Fewleaf Sunflower
Helianthus paradoxus : Paradox Sunflower
Helianthus pauciflorus
Helianthus pauciflorus ssp. pauciflorus : Stiff Sunflower
Helianthus pauciflorus ssp. subrhomboideus : Stiff Sunflower
Helianthus petiolaris
Helianthus petiolaris ssp. fallax : Prairie Sunflower
Helianthus petiolaris ssp. petiolaris : Prairie Sunflower
Helianthus porteri : Porter's Sunflower
Helianthus praecox
Helianthus praecox ssp. hirtus : Texas Sunflower
Helianthus praecox ssp. praecox : Texas Sunflower
Helianthus praecox ssp. runyonii : Runyon's Sunflower
Jerusalem Artichoke (Helianthus tuberosus)Helianthus praetermissus : New Mexico Sunflower
Helianthus pumilus : Little Sunflower
Helianthus radula : Rayless Sunflower
Helianthus resinosus : Resindot Sunflower
Helianthus salicifolius : Willowleaf Sunflower
Helianthus schweinitzii : Schweinitz's Sunflower
Helianthus silphioides : Rosinweed Sunflower
Helianthus simulans : Muck Sunflower
Helianthus smithii : Smith's Sunflower
Helianthus strumosus : Paleleaf Woodland Sunflower
Helianthus tuberosus : Jerusalem Artichoke, Sunchoke