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Hemerocallis lilioasphodelus.jpg
Hemerocallis lilioasphodelus
Scientific classification e
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Asphodelaceae
Subfamily: Hemerocallidoideae
Genus: Hemerocallis
Type species
Hemerocallis lilioasphodelus
  • Lilioasphodelus Fabr.
  • Cameraria Boehm. in C.G.Ludwig

A daylily is a flowering plant in the genus Hemerocallis /ˌhɛmɪrˈkælɪs/.[2] Gardening enthusiasts and professional horticulturalists have long bred daylily species for their attractive flowers. Thousands of cultivars have been registered by local and international Hemerocallis societies.[3] Hemerocallis is now placed in family Asphodelaceae, subfamily Hemerocallidoideae, but used to be part of Liliaceae (which includes true lilies).

The name Hemerocallis comes from the Greek words ἡμέρα (hēmera) "day" and καλός (kalos) "beautiful".


Daylilies on Block Island, Rhode Island.
The Orange Daylily (Hemerocallis fulva) in China

Daylilies are perennial plants, whose name alludes to the flowers which typically last no more than 24 hours (about a day or so). The flowers of most species open in early morning and wither during the following night, possibly replaced by another one on the same scape (flower stalk) the next day. Some species are night-blooming. Daylilies are not commonly used as cut flowers for formal flower arranging, yet they make good cut flowers otherwise as new flowers continue to open on cut stems over several days.

Hemerocallis is native to Asia, primarily eastern Asia, including China, Korea, and Japan. This genus is popular worldwide because of the showy flowers and hardiness of many kinds. There are over 80,000 registered cultivars. Hundreds of cultivars have fragrant flowers, and more scented cultivars are appearing more frequently in northern hybridization programs. Some earlier blooming cultivars rebloom later in the season, particularly if their capsules, in which seeds are developing, are removed.

Most kinds of daylilies occur as clumps, each of which has leaves, a crown, flowers, and roots. The long, linear lanceolate leaves are grouped into opposite fans with arching leaves. The crown is the small white portion between the leaves and the roots. Along the scape of some kinds of daylilies, small leafy "proliferations" form at nodes or in bracts. A proliferation forms roots when planted and is often an exact clone of its parent plant. Many kinds of daylilies have thickened roots in which they store food and water.

A normal, single daylily flower has three petals and three sepals, collectively called tepals, each with a midrib in either the same basic color or a different color. The centermost part of the flower, called the throat, usually is of a different color than the more distal areas of the tepals. Each flower usually has six stamens, each with a two-lobed anther. After successful pollination, a flower forms a botanical capsule (often erroneously called a pod since botanical pods are found in Fabaceae, not Hemerocallis).

The orange or tawny daylily (Hemerocallis fulva), common along roadsides in much of the United States, is native to Asia.

Hemerocallis species are toxic to cats and ingestion may be fatal. Treatment is usually successful if started before renal failure has developed.[4]



Hemerocallis fulva, illustration of 1885
The Tawny Daylily (Hemerocallis fulva)
Hemerocallis thunbergii

The World Checklist of Selected Plant Families recognizes 19 species as of September 2014:[1]

Two hybrids are recognized:[1]

  • Hemerocallis × exilis Satake = H. fulva var. angustifolia × H. thunbergii
  • Hemerocallis × fallaxlittoralis Konta & S.Matsumoto = H. littorea × H. thunbergii

A number of hybrid names appear in the horticultural literature but are not recognized as valid by the World Checklist of Selected Plant Families. These include:[1]

  • H. × hybrida
  • H. × ochroleuca
  • H. × stoutiana
  • H. × traubara, H. × traubiana
  • H. × washingtonia
  • H. × yeldara, H. × yeldiana


The daylily is generally referred to as "the perfect perennial" by gardeners, due to its brilliant colors, ability to tolerate drought and frost and to thrive in many different climate zones, and generally low maintenance. It is a vigorous perennial that lasts for many years in a garden, with very little care and adapts to many different soil and light conditions.[5] Daylilies have a relatively short blooming period, depending on the type. Some will bloom in early spring while others wait until the summer or even autumn. Most daylily plants bloom for 1 through 5 weeks, although some bloom twice in one season ("rebloomers)".[6]

The orange daylily (Hemerocallis fulva), and the sweet-scented lemon-lily (H. lilioasphodelus; H. flava, old name) were early imports from England to 17th-century American gardens and soon escaped from gardens. The introduced orange daylily, although not a true lily, is now common in many natural areas, where it is considered an invasive species.


H. 'Ruby Spider'
H. 'Kwanzo' – a triple-flowered triploid cultivar
H. 'Red Magic'
H. 'Wayside King Royale'
A Hemerocallis lilioasphodelus cultivar growing in Venezuela

There are more than 80,000 daylily cultivars.[5] Depending on the species and cultivar, daylilies grow in USDA plant hardiness zones 1 through 11, making them some of the more adaptable landscape plants. Hybridizers have developed the vast majority of cultivars within the last 100 years. The large-flowered, bright yellow Hemerocallis 'Hyperion', introduced in the 1920s, heralded a return to gardens of the once-dismissed daylily, and is still widely available in the nursery trade. Daylily breeding has been a specialty in the United States, where daylily heat- and drought-resistance made them garden standbys since the 1950s. New cultivars have sold for thousands of dollars,[citation needed] but many sturdy and prolific cultivars sell at reasonable prices of US$20 or less.

Hemerocallis is one of the very highly hybridized plant genera. Hybridizers register hundreds of new cultivars yearly. Hybridizers have extended the genus' color range from the yellow, orange, and pale pink of the species, through vibrant reds, purples, lavenders, greenish tones, near-black, near-white, and more. However, hybridizers have not yet been able to produce a daylily with primarily blue flowers in forms of blue such as azure blue, cobalt blue, and sky blue. Flowers of some cultivars have small areas of cobalt blue.

Other flower traits that hybridizers developed include height, scent, ruffled edges, contrasting "eyes" in the center of a bloom, and an illusion of glitter which is called "diamond dust." Sought-after improvements include foliage color and variegation and plant disease resistance and the ability to form large, neat clumps. Hybridizers also seek to make less-hardy plants hardier in Canada and the Northern United States by crossing evergreen and semi-evergreen plants with those that become dormant and by using other methods. Many kinds of daylilies form clumps of crowded shoots. It is possible to dig up every 3 or so years, separate shoots, and replant only some of the shoots to reduce crowding. This process increases the flowering of many cultivars.

In the last several decades, many hybridizers have focused on breeding tetraploid plants, which tend to have sturdier scapes and tepals than diploids and some flower-color traits that are not found in diploids. Until this trend took root, nearly all daylilies were diploid. "Tets," as they are called by aficionados, have 44 chromosomes, while triploids have 33 chromosomes and diploids have 22 chromosomes per individual plant.[7] Hemerocallis fulva 'Europa', H. fulva 'Kwanso', H. fulva 'Kwanso Variegata', H. fulva 'Kwanso Kaempfer', H. fulva var. maculata, H. fulva var. angustifolia, and H. fulva 'Flore Pleno' are all triplods that almost never produce seeds and reproduce almost solely by underground runners (stolons) and dividing groups by gardeners. A polymerous daylily flower is one with more than three sepals and more than three petals. Although some people[who?] synonymize "polymerous" with "double," some polymerous flowers have over five times the normal number of petals.

Formerly daylilies were only available in yellow, pink, fulvous (bronzed), and rosy-fulvous colors, now they come in an assortment of many more color shades and tints thanks to intensive hybridization. They can now be found in nearly every color except pure blue and pure white. Those with yellow, pink, and other pastel flowers may require full sun to bring out all of their colors; darker varieties, including many of those with red and purple flowers are not colorfast in bright sun.


The highest award a cultivar can receive in the United States is the Stout Silver Medal, given in memory of Dr. Arlow Burdette Stout, who is considered to be the father of modern daylily breeding in North America. This annual award—as voted by American Hemerocallis Society Garden judges—can be given only to a cultivar that has first received the Award of Merit not less than two years previously. The 2014 winner of the Stout Silver Medal is 'Webster's Pink Wonder', hybridized by Richard Webster and introduced by R. Cobb. A complete list of Stout Silver Medal winners can be seen on the AHS website.[8]

In the UK the following cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-[9]

  • 'All American Chief'
  • 'Always Afternoon'
  • 'Arctic Snow'
  • 'Asterisk'
  • 'August Frost'
  • 'Beauty to Behold'
  • 'Burning Daylight'[10]
  • 'Cat Dancer'
  • 'Cayenne'
  • 'Cherry Eyed Pumpkin'
  • H. citrina
  • 'Condilla'
  • 'Curly Cinnamon Windmill'
  • 'Custard Candy'
  • 'Eggplant Escapade'
  • 'Elegant Candy'
  • 'Fooled Me'
  • 'Grey Witch'
  • 'Holly Dancer'
  • 'Jamaican Me Crazy'
  • 'Jellyfish Jealousy'
  • 'Julie Newmar'
  • 'Karen's Curls'
  • 'Killer'
  • 'Lady Neva'
  • 'Lime Frost'
  • 'Mahogany Magic'
  • 'Mary's Gold'
  • 'Moonlit Masquerade'
  • 'North Wind Dancer'
  • 'Old Tangiers'
  • 'Performance Anxiety'
  • ‘Pink Damask’[11]
  • 'Primal Scream'
  • 'Radiant Moonbeam'
  • ’Red Precious’[12]
  • 'Ruby Spider'[13]
  • 'Running Late'
  • 'Russian Rhapsody'
  • 'Selma Longlegs'
  • 'Serena Sunburst'[14]
  • 'Sir Modred'[15]
  • 'Spider Man'
  • 'Stafford'[16]
  • 'Strawberry Candy'
  • 'Tuxedo Junction'


Contarinia quinquenotata, commonly known as the daylily gall midge, is a small gray insect infesting the flower buds of Hemerocallis species causing the flower to remain closed and rot.[17] It is a pest within the horticultural trade in several parts of the world, including Southern and Eastern Europe, the United Kingdom, Canada, and the United States.[18]


Dried golden needles

The flowers of Hemerocallis citrina are edible and are used in Chinese cuisine.[19] They are sold (fresh or dried) in Asian markets as gum jum (金针 in Chinese; pinyin: jīn zhēn) or yellow flower vegetables (黃花菜 in Chinese; pinyin: huáng huā cài). They are used in hot and sour soup, daylily soup (金針花湯), Buddha's delight, and moo shu pork.

See also[edit]


  1. ^ a b c d World Checklist of Selected Plant Families, The Board of Trustees of the Royal Botanic Gardens, Kew, retrieved July 19, 2014
  2. ^ Sunset Western Garden Book, 1995:606–607
  3. ^ "International Daylily Groups". American Hemerocallis Society.
  4. ^ Fitzgerald, K.T. (2010). "Lily toxicity in the cat". Topics in Companion Animal Medicine. 25 (4): 213–217. doi:10.1053/j.tcam.2010.09.006. PMID 21147474.
  5. ^ a b "Growing daylilies".
  6. ^ "Dayliles Frequently Asked Questions". American Hemerocallis Society. American Hemerocallis Society, Inc. Retrieved 12 June 2012.
  7. ^ Daylilies Archived 2007-11-06 at the Wayback Machine undated info page at University of Nebraska. Accessed August 1, 2007.
  8. ^ "AHS Awards and Honors: Stout Medal Winners".
  9. ^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 47. Retrieved 3 March 2018.
  10. ^ "RHS Plantfinder - Hemerocallis 'Burning Daylight'". Retrieved 2 March 2018.
  11. ^ "RHS Plantfinder - Hemerocallis 'Pink Damask'". Retrieved 2 March 2018.
  12. ^ "RHS Plantfinder - Hemerocallis 'Red Precious'". Retrieved 2 March 2018.
  13. ^ "RHS Plantfinder - Hemerocallis 'Ruby Spider'". Retrieved 2 March 2018.
  14. ^ "RHS Plantfinder - Hemerocallis 'Serena Sunburst'". Retrieved 2 March 2018.
  15. ^ "RHS Plantfinder - Hemerocallis 'Sir Modred'". Retrieved 2 March 2018.
  16. ^ "RHS Plantfinder - Hemerocallis 'Stafford'". Retrieved 2 March 2018.
  17. ^ "Hemerocallis Gall Midge". American Hemerocallis Society. Retrieved 5 May 2019.
  18. ^ "Continaria quinquenotata". Phytosanitary Alert System. North American Plant Protection Organization. 2014. Retrieved 5 May 2019.
  19. ^ Hemerocallis citrina

External links[edit]

Daylily Societies[edit]