Description from Evolution Plants
This species is, for some reason, rare in cultivation, both in Europe and its native North America, which is a shame, because it is both easy and attractive, in a blowsy, informal sort of way. The bright yellow laminae of the ray florets (the bits that look like petals in a composite flower) droop langurously around the dark central boss of disc florets, in a manner that evokes late summer. It goes very well indeed with a pitcher of mint julep, a deckchair and a novel by P.G. Wodehouse.
The plant grows to about 120cm tall and flowers over a long season in late summer and autumn, attracting insects and associating well with other late-flowering perennials such as Helianthus and Eupatorium.
The tall grass prairies of North America once covered a huge swathe of land from Canada to Texas. Most have gone under the plough or have been developed. The surviving fragments now add up to about 4% of their extent before European colonisation. Many of the species that make up this rich, diverse ecosystem are wonderful garden plants and prominent among these is the genus Rudbeckia. As with so many other horticulturally excellent genera, only one or two species are commonly grown, not because these are better but because they have been mass produced and marketed by wholesalers.