Black-eyed Susan, (Rudbeckia hirta), is a tough, low-maintenance plant that produces yellow or orange blooms with deep brown, cone-like centers throughout summer and fall. At maturity, the plant reaches heights of up to 3 feet. Black-eyed Susan is suitable for U.S. Department of Agriculture plant hardiness zones 2 through 11.
Although black-eyed Susan is a moderately drought-tolerant plant, the soil should never be bone dry. Water only when the top of the soil feels dry, as Black-eyed Susan is prone to rot in muddy soil. To produce long, healthy roots, provide enough water to soak the roots. Water the soil at the base of the plant, as overhead watering puts the plant at risk for mildew and other moisture-related diseases.
Although black-eyed Susan is tough and pest-resistant, it is sometimes bothered by slugs and aphids. Prevent slugs through proper maintenance of the area around the plant. Rake up leaves, wilted blooms and other plant debris to eliminate hiding places for slugs. A serious infestation may require application of a commercial slug bait. Aphids, tiny green bugs that suck the sap from the undersides and joints of the leaves, can usually be controlled by blasting the plant with a strong stream of water. Otherwise, spray the pests regularly with an insecticidal soap spray. Avoid pesticides, which kill the beneficial insects that feast on aphids, such as ladybugs and lacewings.
Black-eyed Susans benefit from division every three to four years, which keeps the plant healthy and vibrant. Dig up an entire clump and then divide it into smaller sections, each with a healthy root system. Plant the sections in a sunny, well-drained area. Discard the old, nonproductive center of the plant and add it to the compost pile. Black-eyed Susan is best divided in fall. Before dividing, cut the plant down nearly to the ground.
Regular deadheading encourages black-eyed Susan to bloom prolifically all season. Without deadheading, the plant goes to seed early and blooming rapidly declines. To deadhead, pinch or cut blooms as soon as they wilt. Remove the wilted blossom, along with the stem, down to the next leaf or bud. Cut fresh black-eyed Susans for bouquets frequently.
Your Planting Articles
- University of Florida IFAS Extension: Rudbeckia Hirta, Black-Eyed Susan, Gloriosa Daisy
- The Old Farmer's Almanac: Black-Eyed Susans
- East Cherry Creek Valley Water and Sanitation District: Rudbeckia Fulgida "Goldstrum": "Black-Eyed Susan"
- The New Sunset Western Garden Book; Kathleen Norris Brenzel
- Medioimages/Photodisc/Photodisc/Getty Images