Daylilies (Hemerocallis) are reliable, resilient perennials celebrated for their hardiness and colorful, trumpet-shaped blooms. They form dense clumps of foliage and fleshy roots, making them staples in many garden designs. Regular division is a necessary maintenance practice to sustain their health, ensure continued vigor, and maximize flower production. This process revitalizes overcrowded plants, preventing the decline that comes from competition for nutrients and space within the tight root mass.
Determining the Right Time and Necessity
Observing the plant’s health provides the best indication of when division is needed, typically every three to five years. A reduction in the number or size of blooms is a common sign that the dense root system is struggling to provide adequate nutrition to the entire clump. You may also notice the center of the plant becoming thin, unproductive, or dying out as the older roots become woody and congested. This congestion forces new growth to the perimeter, leaving a less attractive ring of foliage.
The most suitable times for this procedure are either in late summer to early fall, shortly after the plant has finished blooming, or in early spring as new growth first emerges. Fall division allows the newly separated plants several weeks to establish their root systems before the onset of winter dormancy. Dividing in the fall also avoids stressing the plant during its main growing and flowering periods, ensuring better recovery.
Preparation and Excavation
Gathering the right equipment simplifies the physical task of lifting and separating the dense root ball. A sturdy garden fork, a long-handled spade, a sharp knife, and a hose or bucket of water are the basic tools required. Preparing the plant one day prior to division by watering it deeply will moisten the soil, making the digging significantly easier and reducing stress on the roots.
To safely lift the clump, begin by using the spade or fork to cut a circle around the perimeter of the foliage, extending the cut six to twelve inches out from the plant’s base. This ensures you capture the majority of the root system without causing excessive damage. Work underneath the root ball, using leverage to gently lift the entire mass out of the ground. Lift the plant from beneath the crown—the point where the roots and leaves meet—to avoid unnecessary trauma to the growth points.
The Separation Process
With the entire clump removed, the next step involves removing the excess soil to clearly expose the roots and the individual growth points, known as “fans.” Shaking off loose soil is a good start, but using a strong stream of water from a hose or soaking the clump will wash away the remaining dirt, allowing for a better view of the root structure. This cleaning process helps you identify the natural divisions and any dead or unhealthy sections.
For smaller, less congested clumps, separation can often be accomplished by hand, gently teasing the fans apart where the root systems are loosely connected. When dealing with larger, more stubborn clumps, a pair of garden forks inserted back-to-back into the center of the mass can be used to pry the clump apart into smaller, more manageable sections. For extremely dense or woody root masses, a sharp, clean knife, spade, or even a saw may be necessary to cut through the congestion. Each resulting division should contain a cluster of healthy, fleshy roots supporting at least two or three foliage fans to ensure successful re-establishment.
Replanting and Post-Division Care
Before replanting the divisions, prepare the new site by loosening the soil and incorporating organic material like compost, which aids in drainage and provides initial nutrients. Dig a hole wide enough to comfortably accommodate the spread-out roots of the division, creating a small mound of soil in the center of the hole. The crown of the daylily—the junction between the roots and the leaves—must be positioned at or just slightly below the soil surface, no deeper than it grew previously.
Spread the roots over the central mound of soil before backfilling with dirt. The most pressing step after planting is a thorough, deep watering to settle the soil around the roots and eliminate any air pockets. Consistent moisture is paramount for the first few weeks as the plant works to establish new feeder roots. Applying a balanced, slow-release fertilizer can encourage new growth, and a layer of mulch around the base of the plant will help retain soil moisture as the divisions recover.