9. Split personalities.
Rudbeckia can be single or double, short or tall, black-eyed or green-eyed. R. hirta ‘Prairie Sun’, sometimes called gloriosa daisy, is short-lived with a green button and golden petals tipped in paler yellow. ‘Cherry Brandy’ is a stunning burgundy-red and blooms for months in a mid-sized mound. On the other hand, the tall heritage plant, R. laciniata ‘Hortensia’ has double, pom-pom-type blooms. R. speciosa var. sullivantii, the showy rudbeckia, is long-lived under the right conditions, living up to 10 years.