Hemerocallis

Basic Information

Common Name: Hemerocallis

Scientific Name: Hemerocallis

Native Habitat: Hemerocallis species are native to various regions across Asia, including China, Korea, Japan, and parts of eastern Russia and Siberia. They are typically found growing in grasslands, woodlands, slopes, and rocky areas.

History / Discovery / Cultivator

Daylilies, belonging to the genus Hemerocallis, boast a long and fascinating history intertwined with human cultivation. While the exact point of their ‘discovery’ in a Western sense is difficult to pinpoint, these plants have been cultivated in East Asia for millennia, not only for their ornamental beauty but also, in some cases, for their edible flower buds and roots. Early records in China suggest their presence and use dating back centuries, indicating a deep understanding and appreciation within indigenous cultures.

The introduction of Hemerocallis to the Western world was a gradual process. Early species like Hemerocallis fulva (Orange Daylily) and Hemerocallis lilioasphodelus (Lemon Daylily) were among the first to arrive in Europe, likely brought back by botanists, missionaries, or traders in the 16th or 17th centuries. These initial introductions were primarily the wild species found naturally in Asia and were appreciated for their hardiness and vibrant blooms, though the flowering period of any single flower lasts only one day, giving rise to the common name “daylily” (from the Greek words *hemera* meaning “day” and *kallos* meaning “beauty”).

The true explosion in the diversity and popularity of daylilies in the West didn’t occur until the late 19th and especially the 20th century. This period marked the beginning of extensive hybridization efforts. Enthusiastic gardeners and professional hybridizers began cross-pollinating different species and existing cultivars to create new flower forms, colors, patterns, and bloom times. A pivotal figure in this early era of systematic daylily breeding was Dr. Arlow Burdette Stout, an American botanist who worked at the New York Botanical Garden in the early to mid-20th century. Stout is often considered the “father of modern daylily breeding” due to his groundbreaking research into the genetics and breeding of Hemerocallis. His work demonstrated the potential for creating a vast array of new cultivars and laid the scientific foundation for future hybridizers.

Following Stout’s lead, countless amateur and professional hybridizers around the world dedicated themselves to improving and diversifying daylilies. Organizations like the American Daylily Society (formerly the American Hemerocallis Society), founded in 1946, played a crucial role in promoting daylilies, registering new cultivars, and fostering a community of growers and hybridizers. This collective effort has transformed Hemerocallis from a genus with a few wild species into one with tens of thousands of registered cultivars, exhibiting an astonishing range of colors, shapes, sizes, heights, and blooming characteristics. This history of continuous cultivation and dedicated hybridization underscores the enduring appeal and adaptability of the daylily, making it one of the most beloved and widely planted perennials in gardens today.

Plant Care Summary

Botanical Insights

Adaptations

Daylilies possess several adaptations that contribute to their widespread success as garden plants. Their most notable adaptation is the fleshy, tuberous root system. These roots serve as storage organs for water and nutrients, allowing the plant to withstand periods of drought relatively well once established. This robust root system also contributes to their vigorous growth and ability to quickly form dense clumps, which helps them compete with weeds. The short-lived nature of the individual blooms, lasting typically just one day, is offset by the prolific production of flower buds on each scape (flower stalk), ensuring a continuous display over several weeks or even months, especially in reblooming varieties. The plant’s ability to thrive in a wide range of soil types and light conditions, coupled with its tolerance for varying temperatures, demonstrates its remarkable adaptability to diverse environments.

Propagation Methods

The most common and easiest method for propagating Hemerocallis is by division. Daylily clumps naturally expand over time, and periodically dividing them rejuvenates the plant, improves flowering, and provides new plants. Division is typically done in late summer after flowering or in early spring before new growth fully emerges. The clump is dug up, and sections containing roots, crown, and foliage are separated using hands, a sharp knife, or a garden fork. Each section can then be replanted. While daylilies produce seeds, propagation from seed is primarily used by hybridizers aiming to create new varieties, as seeds from hybrid cultivars will not grow true to the parent plant.

Toxicology

The toxicity of Hemerocallis varies depending on the organism. For humans and dogs, ingestion of daylily plant parts is generally considered to cause only mild gastrointestinal upset, such as vomiting or diarrhea, if any reaction occurs at all. The level of toxicity is low. However, for cats, Hemerocallis species (true daylilies) are considered highly toxic and can cause severe, potentially fatal, kidney failure. All parts of the plant are toxic, including the flowers, leaves, stem, pollen, and roots. Even ingesting small amounts, such as chewing on a leaf or licking pollen from their fur, can lead to acute kidney injury. Symptoms in cats can appear within hours of ingestion and include vomiting, lethargy, lack of appetite, increased urination followed by decreased urination, and dehydration. If you suspect a cat has ingested any part of a daylily, immediate veterinary attention is crucial.

Common Problems

Pests:

• Aphids: Small, soft-bodied insects that cluster on new growth and flower buds, sucking sap.
• Spider Mites: Tiny arachnids that cause stippling on leaves, often visible with fine webbing in dry conditions.
• Thrips: Slender insects that feed on developing buds and leaves, causing streaking and distortion.
• Slugs and Snails: Chew ragged holes in leaves, especially new foliage.
• Daylily Gall Midge: A small fly that lays eggs in flower buds, causing them to swell abnormally and fail to open.
• Daylily Rust Mites: Microscopic mites that feed on foliage, causing bronzing, stunted growth, and distorted leaves.

Diseases:

• Daylily Rust: A fungal disease causing orange-yellow powdery spots on leaves and scapes, often leading to premature leaf dieback.
• Leaf Streak: A common fungal disease characterized by reddish-brown spots with yellow streaks or borders along the leaf veins.
• Crown Rot: A fungal disease that affects the base of the plant (crown), causing it to become soft and mushy, leading to the collapse and death of the plant. Often caused by poor drainage or planting too deep.
• Root Rot: Fungal diseases affecting the roots, leading to wilting, yellowing, and poor growth. Also often caused by poor drainage or excessive moisture.

Other:

• Failure to flower: Can be caused by insufficient sunlight (needs at least 6 hours), overcrowding (clump needs division), poor nutrition, or late frosts damaging buds.
• Yellowing leaves: Often indicates overwatering or poor drainage, but can also be caused by underwatering, nutrient deficiencies (especially nitrogen), or natural aging of older foliage.
• Browning leaf tips: Typically caused by inconsistent watering, low humidity, excessive fertilizer salts in the soil, or windburn.

Rarity & Value

Rarity:

Most Hemerocallis species and common cultivars are not considered rare; they are widely available and easy to grow. Rarity in daylilies is usually associated with specific, often newly introduced cultivars that are patented, difficult to propagate quickly, or have unique characteristics (like unusual colors, patterns, or forms) that are in high demand among collectors. Historically significant cultivars or those no longer in widespread commercial production but sought by enthusiasts might also be considered rare. However, the ease of division for most varieties means that true long-term rarity for a well-established cultivar is uncommon unless it is inherently slow-growing or sterile.

Value:

The market value of a Hemerocallis plant can vary dramatically, ranging from a few dollars for a common, mass-produced cultivar at a garden center to hundreds or even thousands of dollars for a single fan (a division with one crown and fan of leaves) of a highly sought-after, award-winning, or very new cultivar from a specialized nursery or hybridizer. Factors influencing value include: the cultivar’s novelty (new introductions are often more expensive), awards received (like the Stout Medal), the quality and stability of its bloom characteristics (color, form, pattern, size), its vigor and ease of growth, supply versus demand, and the reputation of the hybridizer. Size matters to some extent – a larger, more mature division might command a slightly higher price than a single fan, but the cultivar’s desirability is the primary driver of value.