Q. When can I divide Rudbeckia?
Rudbeckia can be divided in early spring or in the fall, usually every 4-5 years. It is best to divide when the plants have become too large or exhibits diminished or small flowers. Dig it up, divided using a spade or garden fork and replanted in newly spaded soil improved with compost or other organic matter.
Rudbeckia cultivation tips: Black-eyed Susans (and coneflowers) are gaining popularity outside of their natural habitat in moist, sun-soaked, well-drained meadows. You can't give them too much sun--the more the better. Moderately fertile, moisture-retentive soil is to their liking--don't let them dry out. To stimulate continued bloom throughout the growth season, remove some of the flowers. New award-winning cultivars such as R. fulgida var. sullivantii 'Goldsturm' are easy to grow. Deadhead spent blooms to keep them looking good (R. fulgida doesn't need dedheading). Pinch out the tips of R. laciniata 'Herbstsonne' when 2 feet tall, to curb its height. Some may need staking. Take stem cuttings in spring, grow from seed, or purchase nursery plants.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service