The plant commonly known as the daylily, scientifically Hemerocallis, is often mistakenly believed to grow from a bulb. Daylilies are actually fibrous-rooted perennials, propagated and sold as bare root divisions or clumps. These clumps consist of fleshy roots and a crown, which is the compressed stem where the roots and leaves meet. Understanding this structure is key, as planting methods and spacing are tailored to these fibrous roots. Daylilies establish best when their roots have proper space to expand immediately after planting.
Standard Daylily Spacing Requirements
The recommended planting distance for most average-sized daylily cultivars is between 18 and 24 inches apart. This range provides the necessary perimeter for the plant’s mature size, allowing the root system to fully develop into a dense, multi-fan clump. Adequate spacing also facilitates proper air circulation around the foliage, helping leaves dry quickly and reducing the risk of fungal diseases like leaf streak. Planting within this range prevents root systems from competing too quickly for soil moisture and nutrients.
The planting distance should be measured from the center of the crown of one plant to the center of the crown of the next. Using the minimum 18 inches allows the daylily to remain undisturbed for several seasons before division is needed. The maximum 24 inches ensures vigorous cultivars have ample room to mature into full-sized specimens.
Factors Influencing Planting Density
A gardener may deviate from standard spacing based on cultivar size and desired aesthetic result. Smaller, miniature daylily cultivars, which have a more compact growth habit, can be planted closer, often as tight as 15 inches apart. Conversely, very large-flowered or vigorous tetraploid varieties may require up to 30 inches to support their larger leaf mass and extensive root growth without quickly becoming overcrowded.
Planting daylilies closer than 18 inches (e.g., 12 to 15 inches apart) is a technique used for mass planting designs. This tight configuration creates an immediate, continuous drift of color and foliage, but it sacrifices long-term spacing for instant visual impact. The trade-off for this instant density is that the plants will require lifting and dividing sooner, typically within three to four years, compared to the five to ten years a well-spaced clump can remain undisturbed.
Essential Steps for Successful Planting
Once the correct horizontal spacing is determined, preparing the bare root division ensures quick establishment. Soak the fleshy roots in lukewarm water for a few hours before planting to rehydrate them. Dig a hole that is wider than the root spread and deep enough to accommodate the full root length.
The proper orientation of the daylily crown is important for growth. Create a small mound of soil at the bottom center of the planting hole, and drape the roots over this cone. Position the crown so it sits no more than one inch beneath the soil surface after backfilling.
Gently fill the hole with soil, tamping lightly to remove large air pockets around the roots. Follow this with a thorough initial watering to settle the soil and bring the roots into close contact with the earth. Applying a thin layer of organic mulch around the newly planted crown helps to conserve soil moisture and regulate soil temperature.