Black-eyed Susan flowers (Rudbeckia) provide perennial color to the flower garden. The bright-yellow petal rays surround the dark-brown, nearly black center cone, which gives the flowers their common name. Several different varieties exist, including both short and tall types. The flowers open in midsummer and continue to bloom into the early fall. Black-eyed Susans require only minimal care and provide consistent blooms as long as their basic needs are met.
Plant black-eyed Susans in a full-sun bed that is well-drained. Work a 2-inch layer of compost into the soil before planting to loosen it and improve drainage.
Water newly planted flowers once a week for the first month, or when the soil begins to feel dry. Moisten the top 6 inches of the soil when irrigating. Established plants only require irrigation during extended dry periods.
Spread a 2-inch layer of mulch over the bed and around the plants once they are 6 inches tall in spring. The mulch prevents soil moisture loss from evaporation and helps prevent weed growth around the flowers.
Remove the old, wilted flowers to improve the appearance of the plant and prevent self-seeding. Cut the flower stems off at the base and discard.
Divide the plants every three to five years, or when the clumps become large and crowded. Dig them up, then tease apart the roots with your fingers, splitting the clump into two. Replant the two clumps immediately. Divide the plants in spring as they begin putting on new growth.
Black-eyed Susans don’t require fertilization, but spreading a thin layer of compost over the bed each spring provides some nutrients.