While most gardeners are likely to be familiar with the "Black-eyed Susan" form of Rudbeckia, there are several species available to gardeners.    Black-eyed susan, (R. fulgida) also known as orange coneflower  or gloriosa daisy, is general compact and relatively short, reaching 24-36" tall for most popular cultivars (pictured bottom)  The most popular cultivar for bedding type plants has been 'Goldsturm'.  Also popular among gardeners have been the many cultivars of R. hirta, such as 'Goldilocks', 'Indian Summer' and 'Cherokee Sunset' (not pictured.)

Far less known is the more stately yellow coneflower (R. nitida), and in particular the cultivar 'Herbstonne' that towers at 7 feet (pictured below).  The bright yellow ray flowers tend to droop downward, leaving the cone of disc flowers more exposed.  These giants bloom beginning in mid to late summer, are a favorite of butterflies, and also make excellent cut-flowers.