Daylilies (Hemerocallis) are hardy perennials prized for their vibrant summer blooms and adaptability. As they mature, they form dense clumps by expanding their root systems and foliage. Dividing these clumps is standard maintenance necessary to restore vigor and ensure consistent flower production. This process creates new, healthy plants and prevents overcrowding.
Visual Cues Daylilies Need Splitting
A daylily clump signals its need for division through several visible changes, often occurring every three to five years. The most noticeable sign is a significant reduction in the number and size of flowers produced each season. An overcrowded plant directs less energy toward forming new flower stalks, resulting in a less impactful display.
The physical structure of the plant also becomes dense and congested. Individual leaf groupings, known as fans, become tightly packed, competing for light, water, and nutrients. This competition can cause the central portion of the clump to become woody and unproductive, sometimes dying out completely. If the plant’s center appears sparse or dead while the edges remain vigorous, division is necessary for rejuvenation.
Optimal Seasonal Timing for Division
The most opportune times for dividing daylilies occur outside of their peak growing and blooming season: early spring or late summer to early fall. These periods minimize stress, allowing the plant to focus energy on root establishment rather than flowering or intense summer heat. The goal is to choose a time when temperatures are moderate and moisture is available.
Dividing in early spring, just as new growth begins and is only a few inches tall, is often preferred. This timing gives the plant a full growing season to establish its root system. Cool soil temperatures and spring rains provide an ideal environment for recovery before the stresses of summer heat arrive.
The second optimal window is late summer or early fall, immediately after the plant has finished flowering. This timing works well as the daylily may enter a natural semi-dormant state, reducing the shock of division. Complete the division at least four to six weeks before the first anticipated hard frost. This establishment period allows the newly separated root systems to anchor themselves and store energy to survive the winter.
Essential Steps for Dividing and Replanting
The process begins by carefully digging up the entire daylily clump using a garden fork or spade, working outside the foliage line to capture the majority of the root mass. Once lifted, gently shake or rinse the soil away from the fleshy roots to expose the crown and individual fans. A clean separation is easier to achieve when the root structure is visible.
To create new plants, separate the clump into smaller sections, ensuring each division retains a healthy portion of roots and at least three to five leaf fans. Large, dense clumps may require a sharp knife, spade, or saw to cut through the compacted crown tissue. Trimming the foliage back to about six to eight inches tall helps reduce water loss, directing the plant’s energy toward root growth.
The new planting site should be prepared with loose, well-draining soil, often incorporating compost. Plant each division so that the crown—where the leaves meet the roots—is set no more than one inch below the soil surface, ideally at ground level. After settling the soil firmly around the roots, the newly planted divisions must receive a thorough, deep watering to eliminate air pockets.