Daylilies, scientifically known as Hemerocallis, are among the most popular and resilient perennial plants in home gardens. These low-maintenance flowers are prized for their adaptability and profuse, trumpet-shaped blooms that appear throughout the summer season. Division is a necessary horticultural task that ensures their long-term health and vigor. Splitting the dense underground clumps is an effective way to maintain a thriving daylily patch and propagate new plants for other areas of the landscape.
Why Division is Needed
The need to divide daylilies arises when their fleshy root systems become overly congested. This overcrowding causes plants to compete intensely for limited resources like water, nutrients, and sunlight, which impacts their overall performance. A thick, dense root mass often leads to a noticeable reduction in the size and quantity of flowers produced, which is a common sign that division is due.
Splitting an overgrown clump every three to five years rejuvenates the daylily by alleviating root congestion. Separating the large mass into smaller divisions allows each new section access to more soil volume and available nutrients. This process effectively resets the plant’s growth cycle, ensuring a return to robust foliage and abundant flowering. It also offers a method for gardeners to propagate their favorite varieties for free.
Optimal Timing for Spring Division
Spring represents the ideal window for dividing daylilies because the plant is just emerging from dormancy and has not yet directed significant energy into flowering. The goal is to perform the division as soon as the soil becomes workable, generally after the threat of a hard freeze has passed. Cooler soil and air temperatures during this period minimize the physiological stress, known as transplant shock, on the newly separated plants.
The best visual cue for timing is when the new, green leaf shoots are only three to eight inches tall. Dividing the plants before the foliage becomes too large makes the process easier to manage and reduces potential damage to the leaves. Starting early provides the new divisions a long period to establish a strong root system before the onset of summer heat and the demand of flower production.
The Division Process
The physical process begins by gathering the necessary tools, such as a sharp spade or garden fork, a knife or small hand saw, and pruning shears. Use the spade or fork to dig a wide circle around the clump, beginning about six to twelve inches outside the perimeter of the foliage. This distance ensures that a substantial portion of the fibrous root ball remains intact.
Gently lift the entire clump from the ground once the soil is loosened, taking care to support the root mass. Excess soil can be brushed off or rinsed away to reveal the individual fans, which are the natural growing points where the leaves meet the roots. Separate the clump into smaller sections using a sharp knife, spade, or by pulling the root mass apart by hand. Ensure each new division, or fan, has a healthy root system and at least two to three growing shoots.
Before replanting, use pruning shears to trim the foliage of each division back to a height of six to eight inches. This reduces moisture loss through the leaves and encourages the plant to focus its energy on new root growth.
Replanting and Follow-Up Care
After the fans are separated, prepare the new planting site by digging a hole slightly wider than the root spread of the division. Incorporating organic matter, such as compost, into the backfill soil helps to improve drainage and nutrient availability. The crown, the point where the roots and the leaves meet, should be positioned at or just slightly below the surrounding soil level, avoiding deep burial.
Spread the roots out evenly within the prepared hole and then backfill with the amended soil, lightly tamping it down to remove air pockets. Immediately after planting, a deep watering is necessary to settle the soil around the roots and minimize transplant shock. For the first few weeks, maintain consistently moist soil, especially during dry periods, to facilitate the development of new feeder roots. Avoid applying high-nitrogen fertilizer at this stage, as the focus should remain on root establishment rather than forcing lush new foliage growth.