Daylilies (Hemerocallis) are popular perennial flowers known for their resilience, adaptability, and cheerful, trumpet-shaped blooms. While low-maintenance, these vigorous plants naturally form dense clumps over time, which eventually hinders their performance and overall health. Dividing the daylily clump is a necessary gardening practice that rejuvenates the plant, ensures continued abundant flowering, and provides new plants for other areas of your landscape.
Identifying When Division Is Necessary
The primary indication that a daylily clump requires division is a noticeable decline in its floral display. A significant reduction in the number or size of the flowers (scapes) is a clear signal of overcrowding. This reduced blooming occurs because the tightly packed roots compete intensely for limited soil resources, leading to malnourishment.
A visual inspection of the foliage can also reveal the need for division. When a daylily becomes too congested, the center of the clump may begin to look sparse, thin, or even “dead” as the oldest fans struggle. The sheer density of the leaves can also increase the plant’s susceptibility to disease or pest issues. Dividing the daylily resolves the root congestion and restores the plant’s vigor.
Recommended Division Frequency and Optimal Timing
The general recommendation for dividing daylilies is every three to five years, though some may wait up to ten years depending on the cultivar and growing conditions. Newer or slower-growing varieties may not need dividing as frequently as older, vigorous types that rapidly form large clumps. The plant’s performance, such as reduced blooms or a dead center, is a more accurate measure of when to divide than following a rigid calendar schedule.
The optimal window for division is either in early spring or late summer to early fall. Dividing in early spring, just as new growth emerges, allows the plant to establish roots before the stress of summer heat and flowering. If dividing later, aim for a period right after the plant has finished blooming. Ensure the division is completed at least four to six weeks before the first hard frost. This late-season timing allows the new divisions to develop a strong root system before winter dormancy.
Step-by-Step Guide to Division
Begin the division process by thoroughly watering the daylily clump the day before you plan to dig it up; this hydrates the roots and makes the soil easier to work with. Use a garden fork or sharp spade to loosen the soil in a wide circle, 6 to 12 inches away from the foliage perimeter. This ensures you capture the majority of the root mass. Carefully lift the entire root ball from the ground, keeping it as intact as possible.
Once the clump is out, shake or rinse away the excess soil to expose the roots and crowns, making separation points visible. For separating densely packed roots, you can use your hands to gently pull apart naturally separating sections. If the roots are extremely tight, insert two garden forks back-to-back into the center of the clump. Pull the handles apart to leverage the mass into smaller sections. Each resulting division should contain at least three to five leaf fans attached to a healthy portion of roots.
Before replanting, use clean shears to trim the foliage back to a height of 6 to 8 inches to minimize moisture loss and reduce transplant shock. When replanting, dig a hole wide enough to accommodate the spread-out roots, amending the soil with compost. Position the division so that the crown—the point where the leaves meet the roots—is just at or slightly below the soil surface. After backfilling the hole and firming the soil, water the newly planted divisions immediately and deeply to settle the soil and aid in establishment.