Greetings from the garden! We, the Black-eyed Susans (Rudbeckia spp.), are a resilient and sun-worshipping bunch. To truly care for us, you must first understand our fundamental, non-negotiable needs, which remain constant regardless of your location. We demand full sun—at least six to eight hours of direct, glorious sunlight daily. Without it, our stems become weak and leggy, and our iconic golden-yellow petals fail to put on a proper show. We also require well-draining soil. While we are tolerant of various soil types, from clay to loam, our roots will rot and succumb to disease if left sitting in constant moisture. Meeting these two basic requirements is the most critical step in ensuring our health and happiness.
For many of our perennial varieties, like Rudbeckia fulgida, your USDA Zones 4 through 7 are our sweet spot. Here, we experience the distinct seasonal chill we need. The cold winter months provide us with a vital period of dormancy, a rest that rejuvenates our root systems and prepares us for vigorous growth in the spring. In these zones, your care can be relatively straightforward. A layer of mulch applied after the ground first freezes helps protect our roots from extreme temperature fluctuations. Come early spring, you can cut our old, dead stems back to the ground to make way for new growth. Watering is generally only necessary during prolonged periods of drought, as we are quite drought-tolerant once established.
As you move into the warmer climates of Zones 8 and 9, the rules of engagement change slightly. The intense, humid heat of a southern summer can be challenging. While we still crave full sun, the scorching afternoon sun in these zones can sometimes cause us stress. A location with morning sun and a bit of light afternoon shade can be beneficial. The primary concern here is soil moisture and air circulation. Humidity fosters fungal diseases like powdery mildew. To combat this, ensure we are spaced adequately apart to promote good air flow around our foliage. Water us at the base in the morning, avoiding wet leaves, to give the sun time to dry us off. We may act as short-lived perennials or even annuals in the hottest parts of these zones.
One of our most defining traits is our vigorous, spreading nature. We propagate ourselves through seeds and by sending out underground runners (rhizomes). In ideal conditions, we can form large, magnificent colonies. However, this enthusiasm can sometimes lead to us overcrowding our neighboring plants. Every two to three years, in early spring or after we finish flowering in the fall, we greatly benefit from being divided. Dig up our clump, gently separate the healthy roots into smaller sections, and replant them. This not only controls our spread but also revitalizes us, ensuring we continue to produce abundant, vibrant blooms season after season, from the cold north to the warm south.
