Daylilies (Hemerocallis) are resilient garden perennials known for their spectacular summer blooms. While they thrive in varied conditions, relying solely on existing soil nutrients often results in reduced flower production and overall plant vigor. Providing a targeted nutritional program is the most effective way to ensure dense, healthy foliage and the maximum display of colorful blossoms. Understanding the specific nutrient ratios and application techniques guides a gardener toward a successful feeding strategy.
Understanding Daylily Nutritional Requirements
The nutritional program for daylilies must balance Nitrogen (N), Phosphorus (P), and Potassium (K), collectively known as N-P-K. Phosphorus is a particularly important component for daylilies, as it plays a direct role in flower and bud formation, energy transfer, and strong root development. To support robust flowering, the central number in a fertilizer ratio should be equal to or greater than the first.
Nitrogen is necessary for healthy, green foliage growth, but too much nitrogen can lead to excessive leaves at the expense of flowers, often called “leafy but no blooms.” A moderate amount of nitrogen is appropriate for building the vigorous clumps needed to support numerous flower scapes. Potassium supports the plant’s overall health, regulating water movement, improving disease resistance, and contributing to winter hardiness.
While a general-purpose balanced fertilizer like 10-10-10 is common, a bloom-boosting ratio such as 5-10-10 or 6-12-12 is often better suited for flower production. Daylilies also benefit from micronutrients like zinc, copper, and magnesium, which are often included in high-quality granular or organic formulations. These minor elements facilitate chlorophyll production and enzyme functions, supporting the plant’s metabolic systems.
Recommended Fertilizer Formulations
Fertilizer choice depends on the gardener’s preference for feeding duration and material type, with options falling into synthetic slow-release, water-soluble, and organic categories. For season-long feeding, slow-release granular formulas are generally preferred for their convenience. A balanced synthetic formula like 10-10-10 or a higher-phosphorus option such as 6-12-12 provides continuous nutrient availability over several months.
Slow-release products use coated granules designed to release nutrients gradually based on soil temperature and moisture. This minimizes the risk of burn and the need for repeated applications. If a quick nutrient boost is preferred, especially around peak blooming season, a water-soluble or liquid fertilizer can be applied. Liquid bloom-boosting formulas are rapidly absorbed and are useful for reblooming cultivars needing encouragement for a second flush of flowers.
Organic options function as soil amendments, enriching the soil structure and providing a gentler, longer-term supply of nutrients. Aged animal manure, compost, or alfalfa meal are excellent choices that also enhance the soil’s microbial life and water retention capabilities. While these organic materials typically have lower N-P-K concentrations than synthetic fertilizers, they provide a steady diet and contribute to overall soil health. Bone meal is another popular organic amendment, valued for its high phosphorus content, which directly supports root and flower development.
Timing and Method of Application
The timing of fertilizer application directly influences the plant’s growth cycle and bloom potential. The primary feeding window occurs in early spring, coinciding with the emergence of new growth fans after the last significant frost. This initial application provides the energy necessary to build strong foliage and establish the foundation for the upcoming flower scapes.
A second, lighter application may benefit reblooming varieties or plants in sandy soils where nutrients leach out quickly. This follow-up feeding should be administered immediately after the first flush of blooms has finished, helping the plant recover and stimulating the development of secondary scapes. Fertilizing in late summer or fall is discouraged in cooler climates, as it encourages tender new growth highly susceptible to winter damage.
When applying granular fertilizer, scatter the product evenly around the perimeter of the daylily clump, extending out to the drip line. Avoid sprinkling the granules directly onto the plant’s crown or the base of the foliage to prevent chemical burn. Following application, the area must be thoroughly watered to dissolve the fertilizer granules and move the nutrients down into the root zone for absorption.
Preventing Over-Fertilization and Burn
Applying too much fertilizer, or applying it incorrectly, causes damage known as fertilizer burn. This damage manifests as browning or yellowing of the leaf tips and margins, resulting from high concentrations of soluble salts drawing moisture out of the plant tissue. Over-fertilization also risks stimulating excessive vegetative growth, leading to abundant, weak foliage but few or small flowers.
To prevent these negative outcomes, always follow the application rates specified on the fertilizer packaging, often using slightly less than the maximum recommended amount. A foundational step is testing the soil every few years to determine existing nutrient levels, which prevents the unnecessary addition of elements already present. If a soil test is not available, a conservative approach is the safest method.
Water management safeguards against root damage when using granular fertilizers. Granules should be applied to soil that is already moist, and the area should be watered again immediately after application to dilute the salts and carry the nutrients into the soil. If accidental contact with the foliage occurs, a quick rinse with a garden hose can wash off the granules and prevent localized leaf burn.