From our perspective, division isn't a horticultural trick; it's our innate survival strategy. We, Black-eyed Susans (*Rudbeckia fulgida* and similar species), are not solitary beings. We grow as a colony, spreading outward from a central point through underground stems called rhizomes. Over time, the center of the clump becomes old, woody, and exhausted. The soil nutrients there are depleted, and our growth becomes congested. By dividing us, you are mimicking our natural cycle of expansion and renewal. You are giving the vigorous, young rhizomes on the outer edges of the clump their own space, water, and sunlight to thrive, while mercifully retiring the tired center. It is how we ensure the colony's continued health and vigor.
Timing is everything, and we communicate our readiness clearly through our growth cycle. The optimal times for division are when we are in a state of dormancy or minimal active growth. Early spring, just as new green shoots (our "eyes") are barely poking through the soil, is ideal. Our energy is concentrated in our roots and rhizomes, ready to fuel a new season of growth. The cool, moist soil of spring reduces the shock of being lifted and separated. Alternatively, early autumn, after our showy flowers have faded but while the soil is still warm, is also acceptable. This gives our new divisions several weeks to establish their root systems before winter's freeze. Attempting this process in the heat of summer is highly stressful, as we are directing all our energy into flowering and are ill-equipped to recover from such a major disturbance.
When the time is right, approach the task with respect for our underground architecture. Using a sharp spade or garden fork, dig a wide circle around the outer perimeter of our foliage, staying about 6 inches away from the outermost stems. This ensures you get most of our root system without severe damage. Gently work the tool underneath the entire clump and lever it out of the ground. You will now see the dense, matted mass of our crown and rhizomes. Place the clump on a tarp or directly on the ground. Your next tool is water; use a gentle spray from a hose to wash away the soil from our roots. This allows you to see exactly what you are working with and minimizes tearing.
Now, observe our structure. You will see a tangle of roots and rhizomes connecting multiple growing points, or "fans," of foliage. Your goal is to create new, self-sufficient plants, each with a healthy section of roots and several growing shoots. For small, loose clumps, your hands may be sufficient to gently tease us apart. For larger, tougher clumps, you may need to use two garden forks inserted back-to-back into the center and levered apart, or even a sharp, sterilized knife or spade to cut through the woody crown. Discard any old, dead, or rotten sections from the center. Each new division should be robust, with a good balance of roots and shoots—think of it as ensuring each new plant has enough engine (roots) to support its body (foliage).
The final step is to give our divisions a new home where they can prosper. Prepare the new planting site with loose, well-draining soil amended with some compost. Dig a hole wide and deep enough to accommodate our roots without bending or crowding them. Place the division in the hole, ensuring the crown (where the roots meet the shoots) is level with the soil surface, not buried deeper than it was originally growing. Backfill the hole, firming the soil gently around our roots to eliminate air pockets. Water us deeply and thoroughly immediately after planting. This initial watering is critical for settling the soil around our roots and providing the hydration needed to overcome the transplant shock and begin growing anew.
