Two very different plants that share a confusing name
Despite the similar common name, daylilies and true lilies are not closely related botanically, and confusing the two can lead to real mistakes — different planting depths, different propagation methods, and even different safety considerations around pets. This article sets out exactly how daylilies and true lilies differ, and why the distinction actually matters for how you grow and handle each one.
Different genus, different family
Daylilies belong to the genus Hemerocallis, in the plant family Asphodelaceae (subfamily Hemerocallidoideae). True lilies belong to the genus Lilium, in the family Liliaceae. Despite sharing “lily” in the common name, the two genera are not closely related, and the resemblance is more a matter of both having showy, trumpet-like flowers than any close evolutionary relationship.
How the plants actually grow
Daylilies grow from a fan of fibrous or somewhat fleshy roots, with strap-like leaves emerging directly from the crown at ground level and flower stems (scapes) rising up separately above the foliage. True lilies grow from an actual bulb — a layered, fleshy underground storage structure — and produce a single upright stem with leaves growing directly along its length, topped by the flower or flowers at the top of the stem. If you dig one up, the difference is immediately obvious: a daylily has a fan of roots and fleshy tubers, while a true lily has a distinct, layered bulb.
How long each flower lasts
This is where daylilies get their name: each individual daylily flower opens in the morning and withers by evening, lasting only a single day, though a healthy scape produces many buds in succession so the overall display lasts for weeks. True lily flowers, by contrast, typically last several days to a couple of weeks per bloom, opening more gradually and persisting considerably longer than any single daylily flower.
Foliage differences
Daylily foliage is strappy, arching, and grows directly from the base of the plant in a fountain-like clump, present for most or all of the growing season depending on dormancy type. True lily foliage grows as individual leaves attached along an upright stem, giving the plant a more columnar, single-stemmed appearance rather than a low, spreading clump.
Propagation
Daylilies are propagated primarily by dividing the clump into sections, each containing several fans and roots — a process covered in our daylily care guide. True lilies are propagated from bulbs, either by separating naturally forming offset bulbs, by scaling (removing individual bulb scales to grow new bulblets), or by growing from seed, which is a slower and more specialised process than daylily division.
Height and garden use
Daylilies range from compact 30–40cm miniatures to statuesque varieties over a metre tall, generally used as a clumping border or feature plant. True lilies vary considerably by species and cultivar, but many popular garden lilies (Asiatic and Oriental hybrids, for example) grow as tall, relatively narrow, upright stems, often used as accent plants or cut flowers rather than as a spreading border plant.
Fragrance
Many true lilies, particularly Oriental hybrids, are prized for a strong, often powerful fragrance that can fill a room or garden bed. Daylilies are generally more subtly scented, with some varieties — particularly paler yellow and cream cultivars — carrying a pleasant but noticeably lighter fragrance than most true lilies.
A safety note for pet owners
This is one of the most practically important differences to understand. True lilies (Lilium species) are highly toxic to cats, with even small amounts of pollen or plant material capable of causing serious kidney damage, and cat owners are strongly advised to avoid keeping true lilies in a garden or home that cats have access to. Daylilies (Hemerocallis) are also considered toxic to cats and are generally treated with the same caution by veterinary sources, even though the toxic mechanism and severity reported can differ between the two genera. Given the shared common name and the seriousness of true lily toxicity in particular, cat owners should treat both plants with caution and consult a veterinarian promptly if a cat is seen chewing on either one.
Edibility
Daylily flowers and buds are eaten in some cuisines, particularly in Chinese cooking, where dried daylily buds (“golden needles”) are a recognised ingredient. True lily bulbs are also eaten in some culinary traditions, particularly certain Lilium species in East Asian cuisine, but edibility varies significantly by species in both genera, and some ornamental cultivars — daylily and true lily alike — are bred from or hybridised with species not intended for consumption. Because of this variability, and the toxicity concerns noted above, it is worth being cautious rather than assuming any given garden variety is safe to eat without specific confirmation.
Which one should you plant?
This is not really an either-or question — many Australian gardens grow both successfully, since they serve different roles. Daylilies work well as a tough, drought-tolerant clumping border plant with a long overall flowering season. True lilies work better as a taller, more architectural accent or cut flower, often with stronger fragrance, but generally needing more consistent moisture and better winter chilling (for many popular hybrids) than daylilies require. If you are short on space or want the lowest-maintenance option, daylilies are usually the easier starting point; if fragrance and cut-flower potential matter more to you, true lilies are worth the slightly higher care requirements.
Telling them apart at a glance
- Growth habit: daylilies form a low, arching clump of foliage; true lilies grow as an upright single stem with leaves along its length.
- Underground structure: daylilies have fleshy roots and fans; true lilies grow from a distinct, layered bulb.
- Flower longevity: daylily flowers last one day each; true lily flowers last considerably longer.
- Fragrance: true lilies are typically more strongly scented than daylilies.
Why the distinction is worth knowing
Beyond satisfying curiosity, understanding the difference between daylilies and true lilies affects practical decisions: how deep to plant them, how to propagate more of them, what kind of display to expect and for how long, and — most importantly — how seriously to take pet safety around each one. Two plants, one shared common name, and genuinely different care requirements underneath.
Daylilies and true lilies are not the only “lilies” that are not actually true lilies — alstroemeria, commonly called the Peruvian lily, is unrelated to Lilium as well, and is worth growing in its own right for its unusually long flowering season.
