The Helianthus genus is the third most productive keystone species group in Washtenaw County, in terms of supporting a range of butterfly and moth caterpillars that feed other animals; Helianthus supports 77 species of caterpillars. Like many members of this genus, this tall, cheerful woodland/oak savanna sunflower is an aggressive spreader--beautiful when naturalized in a large area but potentially too enthusiastic for a small space (though it's easy to weed out). This plant spreads via rhizomes, and sends up 2" yellow flowers on 5' stalks starting in July. A stand of H. divaricatus waving in a summer wind is a lovely sight. Tolerates black walnut.