Black-eyed Susan or Rudbeckia hirta,
Rudbekia is a member of the sunflower family (Asteraceae) and has similar daisy-like flowers. Although black-eyed Susans are also called coneflowers because of their cone-shaped heads, they should not be confused with purple coneflowers (Echinacea purpurea). Both flowers come from the same plant family and require similar growing conditions, but the color and appearance of the flowers differ. Confusion also arises when gardeners come across the black-eyed Susan vine (Thunbergia alata). This unrelated Rudbeckia look-alike is a tender, warm-climate perennial native to Africa.
Varies by species, but the typical range is 3 through 9.
Plants have a long bloom period even without deadheading, typically flourishing from late July until the first frost. Some cultivars, such as ‘Early Bird Gold’, have extended bloom times and will begin flowering in mid to late spring.
Varies dramatically, anywhere from 10 inches to 7 feet, depending on the cultivar.
Flower sizes range from 2 to 9 inches wide and can be single, semi-double, or fully double. The petals range in shade from bright yellow to orange-gold, and some cultivars display flushes of red, bronze or mahogany. The flower’s eye, or center, is actually more dark brown than black, but some cultivars, such as ‘Prairie Sun’, have green centers.
There are about 25 species of Rudbeckia, all native to North America. Many species are actually biennials or short-lived perennials but because they self-sow readily, they often return each spring from seed dispersed the previous fall. Rudbeckia hirta (common black-eyed Susan) and R. fulgida (orange coneflower) are the species most readily available to gardeners and include many of the newest cultivars. However, there are number of other species worth seeking out because of their unique attributes including R. maxima (large coneflower), R. laciniata (tall coneflower), R. triloba (brown-eyed Susan or three-lobed coneflower), R. subtomentosa (sweet coneflower), and R. nitida (shiny coneflower).