From our point of view, the process you call "dividing" is a natural and vital form of propagation. We grow from a central underground structure called a rhizome. Think of this rhizome as our brain and pantry combined; it stores the energy we collect from the sun and sends out roots and shoots to expand our colony. Over time, a single plant can develop into a large, dense clump as the rhizome grows outward. While this is a sign of our success, the center of the clump can become overcrowded and woody, struggling to access enough nutrients and water. This is why we actually welcome your intervention. Dividing helps rejuvenate us, giving each new section the space and resources to thrive independently.
Timing is everything for a successful division with minimal stress. The very best times are during our periods of peak root growth, which occur in the early spring just as our new "eyes" (the pointed buds) begin to emerge from the soil. At this time, we are full of pent-up energy and are eager to grow, allowing us to recover quickly. The other ideal window is in the early fall, after the intense summer heat has passed but while the soil is still warm. This gives our root systems ample time to establish themselves before winter dormancy. Please avoid dividing us in the scorching heat of summer, as the stress of losing foliage and roots combined with high temperatures can be severely damaging, even fatal.
To begin, please water us thoroughly the day before the operation. This reduces transplant shock and makes the soil easier to work with. Using a sharp, clean spade, dig around our entire drip line (the circumference of our foliage) and lift our entire root ball from the ground. Be as gentle as possible to minimize root damage. Once we are out, you will see the mass of rhizomes and roots. You can often pull sections apart with your hands, teasing the individual crowns away from the main clump. For older, tougher clumps, you may need to use a sharp knife or even two garden forks placed back-to-back in the center of the clump to lever us apart. Each new division should have at least three to five eyes and a healthy portion of roots attached to its section of rhizome.
After the division, your job is to help us recover. Replant the new divisions promptly. Dig a hole that is wide and deep enough to accommodate our roots without bending or crowding them. The crown (where the eyes meet the roots) should be planted at the same soil level as we were growing before. Backfill the hole, water us deeply to settle the soil around our roots and eliminate air pockets, and then apply a layer of mulch around (but not on top of) our crown. This mulch will help conserve moisture and regulate soil temperature as we work to re-establish our root systems in our new location. Continue to provide consistent moisture for the next several weeks, shielding us from extreme sun if necessary, and we will reward you with vigorous, healthy growth in the coming seasons.
