All About Hemerocallis

So what are all these hemerocallis terms? 

This guide will help you understand the terminology of describing our daylilies, making it easier to find exactly the flower you are after. Classifications are based on the American Hemerocallis Society (AHS) registration and are representative of the plant and bloom as they presented to the hybridizer at their locale.

For a more thorough guide to the daylily, have a look at the AHS dictionary.

Bloom Size

Hemerocallis are measured across the diameter of their bloom as they naturally stand (not unfurled) in inches to classify them as to the size of their bloom. Wherever you see bloom on Strictly Daylilies, you can expect us to be discussing the size of the flower's face – its bloom.

The categories of bloom size in hemerocallis are:

  • Miniature – less than three inches in diameter
  • Small – from 3 inches up to 4 1/2 inches in diameter.
  • Large – 4 1/2 inches or more in diameter.
  • Extra Large – 7 inches or greater.


The height refers to the average height of the scapes of the hemerocallis which carry the blooms and therefore the height of the bloom, not the foliage of the plant, and are classified as follows:

  • Low – the scapes are from 6 to 24 inches high.
  • Medium – the scapes are from 24 to 36 inches high.
  • Tall – the scapes are more than 36 inches high.


Modern hybrid hemerocallis have a remarkably diverse colour range. Today, the only colours notably lacking are pure white and pure blue and pure black. Needless to say, hemerocallis hybridizers are avidly pursuing these colours. We classify ours by the primary colour you can expect from the blooms:


The 'foliage habit' is the winter behaviour of the daylily foliage or leaves. The foliage habit is loosely categorized as dormant, evergreen, and semi-evergreen.

  • Dormant – loses all foliage in winter, and continues growth in the spring
  • Semi-Evergreen – intermediate foliage, not completely dormant, nor evergreen
  • Evergreen – retains foliage throughout the year although it may freeze.


Hemerocallis blooms have a wide array of different forms or shapes. Currently, the AHS officially recognizes the following forms for exhibition purposes: single, double, spider, unusual form, and polymerous. We include other terms here as well.

  • Single Form Hemerocallis

    – 2 whorls, one with 3 petals and one with 3 sepals. (photo of H. Bali Hai)
  • Double Form Hemerocallis

    – contains more than one petal or stamen whorl (looks like a second flower head). Often denoted by a percentage of the time it presents as double. (photo of Hemerocallis Ikebana Star)
  • Spider Form of Hemerocallis

    – petals and sepals are much longer in proportion to their width with a length-to-width ratio of at least 4 to 1. (Photo of H. Belly Button Slipknots)
  • Unusual Form (UF) Hemerocallis

    – this includes crispate (pinched, twisted, or quilled floral segments); cascading (narrow curling or cascading segments); and spatulate (segments markedly wider at the end like a kitchen spatula). (Photo of the outstanding H. Papa Goose, Douglas-Heidi, Browns Ferry Gardens)
  • Polymerous Form (Poly) Hemerocallis

    – more than the normal 3 sepals in the outer whorl and a matching number of petals in the inner whorl. Often denoted by a percentage of the time it presents as polymerous. (Photo of H. Star Poly)
  • Multiform Hemerocallis

    – some daylilies may present with more than one form and may be registered with more than one form. (Photo of H. Cooler Than Me)
  • Self

    – petals and sepals are all the same shade of the same colour. (Photo of Hemerocallis Sweet Pea)
  • Blend

    – flower segments are a blend of two colours; petals and sepals are the same blend. (Photo of Hemerocallis  Children's Festival)
  • Bicolour

    – petal and sepals are of a completely different colour. (Photo of Hemerocallis Dipped in Ink)
  • Bitone

    – lighter outer segments and darker inner segments of a colour. (Photo of Hemerocallis Final Touch)
  • Reverse Bitone

    – lighter inner segments and outer darker segments of a colour.
  • Edged Daylily

    – distinct colouring along the edge of each flower segment (Photo of Hemerocallis Granny Coot)
  • Picotee Edge

    - an ‘edge’ that differs in colour from the flower's base colour. (Photo of Hemerocallis Happy Apache)
  • Ruffled Edge

    – a wavy edge (like a pie-crust) which may be very loose and deep or tightly compressed. (Photo of Hemerocallis Enchanted Forest)
  • Projections On Edge

    – visible protrusions on the edge that may resemble teeth, knobs, horns, tentacles, fringes, or rips. (Photo of 'teeth' on H. Eight Miles High)
  • Recurved

    – edges of bloom curve back towards the stem, creating a rounded shape.
  • Patterned

    – variations in hue, value or saturation of the base, midrib, or throat colour, in such a way that a design is created beyond that of a bold or solid eye, band, halo or watermark, with or without simple picotee edging. (Photo of Hemerocallis Bodacious Pattern)
  • Eyezone

    – darker colouring toward the centre of the bloom on the petals and sepals. (Photo of Hemerocallis Jason Salter)
  • Band

    – darker coloured area just above the throat of a flower only on petals. (Photo of H. Cat Dancer)
  • Halo

    – An eye that is relatively narrow or indistinct. 
  • Watermark

    – a zone above the flower’s throat which is lighter in colour than the petal colour.
  • Veining

    – base colour and the veins within the tepals are of a contrasting colour. (Photo of Hemerocallis Open Hearth)
  • Diamond Dusting

    – structures that produce a glitter-like quality on the petal surface. When the sparkles appear white, it is referred to as diamond dusting. Some of these reflections on yellow cultivars appear to be gold and yellow - these may be called gold dusting. (Photo of Hemerocallis Mike Reed)
  • Tetraploid

    – four identical sets of chromosomes in each cell.
  • Diploid

    – two identical sets of chromosomes in each cell.
  • Extended Blooming Daylily

    – flowers that remain open 16 hours or more.
  • Nocturnal Daylily

    – flowers that open later in the day and remain open during the night and perhaps all or part of the following day.
  • Diurnal Daylily

    – flowers that open early in the morning or during the day.
  • Reblooming, Recurrent, Remontant

    – having more than one cycle of flowering per year.
  • Branching

    – stems originate from the primary scape and bears two or more buds.
  • Bud count

    – the number of buds each scape carries is indicative of how many flowers the plant will bear on a single scape.


All hemerocallis are summer bloomers but different hemerocallis varieties come into flower at different times of the summer. This can vary significantly from one area of the country to another and is dependent on our weather in early spring so it is difficult to place a month on the time a particular cultivar will bloom. We classify ours from early to late according to the American Hemerocallis Society official statistics which refer to the cultivar's initial bloom in the summer. Additionally many hybrids are re-bloomers which send up scapes at some point after the initial bloom.


American Hemerocallis Society Award Guide

  • Honorable Mention: This is the Society's first official stamp of approval beyond the local or regional level.
  • Award of Merit: Given to those hemerocallis cultivars that are not only distinctive and beautiful but have proven to be good performers over a wide geographic area.
  • Stout Silver Medal: This is the Society's highest honour. that a daylily cultivar can receive, given in memory of Dr Arlow B Stout, considered the father of modern daylily hybridizing. Only one daylily variety per year receives the Stout Silver Medal Award. Winners must have previously received Award of Merit and Honorable Mention to qualify.
  • Junior Citation:The AHS Junior Citation is awarded for the primary purpose of focusing attention on new and not yet introduced daylily cultivars that appear to have outstanding qualities and distinction. 
  • Donn Fisher Memorial Award: Given annually for the most outstanding miniature hemerocallis cultivar.
  • Annie T. Giles Award: Given annually to the most outstanding small flowered daylily.
  • Lambert/Webster Award: Given annually to recognize the daylily with best unusual form.
  • Lenington All-American Award: The only varietal award made by the AHS Board of Directors, given to the hemerocallis cultivar for outstanding performance in all AHS regions.
  • Ida Munson Award: Given annually to the most outstanding double hemerocallis cultivar.
  • R.W. Munson Award: Given annually to the best-patterned hemerocallis cultivar.
  • L. Ernest Plouf Award: Given annually to the most consistently fragrant, dormant cultivar.
  • Don C. Stevens Award: Given annually to the most outstanding eyed or banded cultivar.
  • Harris Olson Spider Award: Given annually to the best spider variant.
  • Eugene S. Foster Award: Given annually for the outstanding late-blooming cultivar.

British Hosta and Hemerocallis Society

Newbold Hemerocallis Vase: Given to an outstanding hemerocallis cultivar raised in the UK or Europe.

The Royal Horticultural Society

Award of Garden Merit (AGM):

  • It must be of outstanding excellence for ordinary garden decoration or use
  • It must be available
  • It must be of good constitution
  • It must not require highly specialist growing conditions or care
  • It must not be particularly susceptible to any pest or disease
  • It must not be subject to an unreasonable degree of reversion in its vegetative or floral characteristics