Daylilies are resilient and popular perennial plants, prized by gardeners for their vibrant colors and adaptability. The common name “daylily” is a direct reference to a striking characteristic of the plant’s bloom cycle, and understanding this feature explains the origin of its familiar title. This plant’s name is also deeply rooted in its ancient botanical classification.
The Ephemeral Bloom Cycle
The most direct answer to why these plants are called daylilies lies in the short lifespan of each individual flower. A single bloom typically opens fully in the morning and then withers or fades by nightfall. This ephemeral nature means that each flower lasts for approximately one day, hence the name “daylily.”
This brief flowering period is not a sign of poor health but a deliberate biological strategy. The plant compensates for the short life of each blossom by producing a large number of buds on a single stalk, called a scape. These buds open in succession over a period of weeks, ensuring the plant maintains a continuous display of color throughout the blooming season. A mature daylily clump can produce hundreds of flowers, with only a small number open on any given day.
The Scientific Name and Its Ancient Meaning
The formal botanical name for the daylily, Hemerocallis, reinforces the meaning of its common name. The genus name is derived from two words in ancient Greek that describe the plant’s unique flowering habit. These two roots are Hemera, meaning “day,” and Kallos, which translates to “beauty.”
The combination of these Greek words perfectly encapsulates the plant’s defining characteristic: its beauty is short-lived, lasting only a single day. This nomenclature reveals that botanists observed the same striking, one-day bloom cycle centuries ago. The scientific name, Hemerocallis, serves as an ancient parallel to the modern common name.
Daylilies Are Not True Lilies
The second half of the common name, “lily,” is a misnomer, as daylilies are not true lilies from a botanical standpoint. True lilies belong to the genus Lilium and the family Liliaceae. Daylilies, conversely, belong to the genus Hemerocallis and are currently placed in the family Asphodelaceae, a taxonomic distinction that separates them.
The physical structures of the plants confirm this separate classification. True lilies grow from a scaly, underground bulb used for nutrient storage. Daylilies, however, grow from a crown with a mass of fleshy, tuberous roots. Furthermore, true lilies have foliage arranged along the flower stem, while daylilies have long, grass-like leaves that grow in a clump directly from the base.