Basic Information
Common Name: Yellow Daylily
Scientific Name: Hemerocallis lilioasphodelus
Native Habitat: Native to parts of Siberia, northern China, Korea, and Japan, with a history of naturalization in central Europe.
History / Discovery / Cultivator
The history of the Yellow Daylily, Hemerocallis lilioasphodelus, is deeply intertwined with human civilization, particularly in East Asia, dating back thousands of years. Unlike many ornamental plants whose origins are tied to modern botanical expeditions or specific “discoveries,” this species, often referred to as the Lemon Lily or Custard Lily due to its fragrance and soft yellow hue, was likely first recognized and utilized by people for its practical properties long before it became a garden staple in the West.
Historical records suggest that various Hemerocallis species, including H. lilioasphodelus, were cultivated in China as early as the Han Dynasty (206 BC – 220 AD). Ancient texts, such as the Classic of Poetry (Shijing), mention the plant, highlighting its long-standing presence in Chinese culture. It was valued not only for its beauty but also for its young shoots and flower buds, which were (and still are in some cuisines) consumed as a vegetable. Furthermore, the plant held significance in traditional Chinese medicine, believed to have calming and medicinal properties. This early cultivation and use indicate a profound level of interaction and understanding of the plant’s lifecycle and growth habits by ancient peoples.
The introduction of Hemerocallis lilioasphodelus to the Western world is less precise in terms of a single ‘discoverer’ but is part of the broader exchange of plants that occurred via trade routes and later, botanical exploration. It was among the early Asian plants to reach Europe, likely in the 16th or 17th century. European botanists and gardeners gradually incorporated it into their collections, admiring its hardiness and cheerful summer blooms.
Carl Linnaeus, the father of modern taxonomy, formally described the species in his seminal work Species Plantarum in 1753, giving it the scientific name Hemerocallis lilioasphodelus. The genus name Hemerocallis comes from the Greek words hemera meaning “day” and kallos meaning “beauty,” referencing the ephemeral nature of individual flowers, which typically last only one day. The specific epithet lilioasphodelus suggests a likeness to both true lilies (Lilium) and asphodel (Asphodelus), though daylilies belong to a different plant family (Asphodelaceae).
While specific cultivators responsible for popularizing H. lilioasphodelus in the Western garden world are not as distinctly recorded as with some later cultivars, its resilience, ease of growth, and charming appearance ensured its steady spread. It became a common feature in cottage gardens and perennial borders across Europe and North America. Its robust nature and ability to thrive in a variety of conditions made it a reliable garden plant, often shared between gardeners through simple division of clumps. Its genetic material has also undoubtedly contributed to the vast number of hybrid daylilies (Hemerocallis x hybrida) that exist today, although H. lilioasphodelus itself remains a valued species for its pure form and classic traits. Its journey from an ancient food and medicinal source in East Asia to a beloved, low-maintenance garden perennial worldwide speaks to its enduring appeal and adaptability.
Plant Care Summary
| Category | General Requirement | Notes |
|---|---|---|
| Light | Full Sun to Part Shade | Best flowering in full sun (6+ hours); tolerates part shade but with fewer blooms. |
| Water | Moderate | Drought tolerant once established but performs best with consistent moisture, especially during bloom. |
| Humidity | Average | Thrives in typical outdoor humidity levels; no special requirements. |
| Temp. Range | Hardy (Zones 3-9) | Extremely cold hardy; tolerates a wide range of temperatures; requires a chilling period for dormancy. |
| Soil Type | Adaptable, Well-drained | Prefers fertile, loamy, well-drained soil but tolerates clay, sand, and various pH levels. |
| Fertilizer | Low to Moderate | Generally not heavy feeders; a balanced slow-release fertilizer in spring can enhance flowering. |
| Toxicity | Generally Non-Toxic | Typically listed as non-toxic to humans and pets, but ingestion can potentially cause mild upset. |
Botanical Insights
Adaptations
Hemerocallis lilioasphodelus, the Yellow Daylily, possesses several key adaptations that contribute to its success as a hardy and widespread perennial. Its most significant adaptation lies in its robust, fleshy root system, consisting of rhizomes and thickened storage roots. These structures serve as reservoirs for water and nutrients, enabling the plant to survive periods of drought and harsh winter conditions. The rhizomatous spread allows the plant to form dense clumps, effectively competing with weeds and stabilizing soil. The “daylily” characteristic, where individual flowers last only one day, is tied to its reproductive strategy; while short-lived, the plant produces a succession of blooms over several weeks, maximizing the chances of pollination by various insects. Its ability to thrive in a wide range of soil types, from sandy to clay, and tolerate varying light conditions (though preferring sun for optimal flowering) further underscores its remarkable adaptability to diverse environments.
Propagation Methods
The most common and effective method for propagating Hemerocallis lilioasphodelus is division of the plant clump. This is typically done in early spring or late summer/early fall. The process involves digging up the entire clump, shaking or washing away excess soil to expose the roots and crowns, and then separating the fan-like sections of foliage and their attached roots. Division can be done by hand for smaller clumps or by using garden forks or knives for larger, more intertwined masses. Each division should have several fans of leaves and a healthy portion of the root system. These divisions are then replanted at the same depth as the original plant and watered well. While H. lilioasphodelus can also be grown from seed produced after flowering, this method takes longer to result in a flowering plant and may not produce offspring identical to the parent plant if pollination involved other daylily varieties.
Toxicology
Regarding toxicology, Hemerocallis lilioasphodelus is generally considered safe and is frequently listed as non-toxic to cats, dogs, and humans by reputable sources such as the ASPCA. Historically, parts of the plant, particularly young shoots and dried flower buds, have been consumed in some cultures without widespread reports of toxicity. However, as with ingesting any plant material not typically part of one’s diet, consumption of large quantities of daylily plant parts could potentially cause mild gastrointestinal upset in sensitive individuals or pets, such as vomiting or diarrhea. It is crucial to differentiate daylilies (Hemerocallis) from true lilies (Lilium), as true lilies are highly toxic to cats and can cause severe kidney failure. If ingestion is suspected in a pet and any adverse symptoms are observed, it is always best to consult a veterinarian.
Common Problems
Pests:
- Aphids (suck sap from buds and foliage)
- Spider Mites (cause stippling on leaves, more common in dry conditions)
- Thrips (feed on flowers and buds, causing distortion or streaking)
- Daylily Gall Midge (larvae cause buds to swell and fail to open)
- Slugs and Snails (chew holes in leaves, especially new growth)
Diseases:
- Daylily Rust (Puccinia hemerocallidis – orange pustules on leaves and scapes)
- Leaf Streak (causes reddish-brown streaks and spots on leaves)
- Crown Rot (fungal issue causing the base of the plant to rot, often due to poor drainage)
- Root Rot (caused by various fungi in waterlogged soil)
Other:
- Non-flowering: Often caused by insufficient sunlight (too much shade), overcrowding of the clump (needs division), or poor soil fertility.
- Short bloom period: Individual flowers last only one day, which is inherent to the “daylily” nature of the plant.
- Yellowing leaves: Can indicate overwatering, underwatering, nutrient deficiency (especially nitrogen), or the natural dieback of old foliage.
- Browning tips: May result from drought stress, excessive fertilizer salts in the soil, or sometimes natural aging of the leaf.
Rarity & Value
Rarity:
The species Hemerocallis lilioasphodelus is not considered rare. It is a common, widely cultivated perennial species known for its hardiness, ease of growth, and ability to naturalize in suitable climates. It has been grown in gardens for centuries and is readily available from nurseries and garden centers worldwide. While some specific hybrid daylily cultivars might be considered rare due to newness, limited availability, or specific desirable traits (like unusual colors or patterns), the foundational H. lilioasphodelus species itself is abundant.
Value:
The market value of Hemerocallis lilioasphodelus plants is generally low to moderate, reflecting its widespread availability and ease of propagation. Plants are typically sold as bare-root divisions or potted specimens. Value factors primarily include the size and maturity of the clump (larger, established clumps ready to flower command a slightly higher price than small divisions) and the health and vigor of the plant. Unlike some rare houseplant species, its value is not typically influenced by traits like variegation (which is not a characteristic of this species) or collector trends focused on scarcity. It is valued for its reliable performance, classic beauty, and low-maintenance nature in the garden.
