Just what is a daylily? Notice that 'daylily' is one word. It is also correctly spelled as two. However spelled, the daylily is not a form of lily (genus Lilium).

The daylily, or more correctly Hemerocallis, is a perennial plant that blooms primarily in midsummer (earlier in the South; later in the far North). The basic plant is often called a 'fan' because the leaves are distichous. This means they are arranged in two vertical rows on opposite sides of the 'crown' or core of the plant, similar to an Iris plant. Thus, the leaves tend to grow in one (flat) geometric plane and take on the general shape of an old-fashioned, hand fan. The plant propagates mainly by expanding its roots, which form new fans. A 'clump' is formed as the plant grows and forms multiple fans.

Each individual daylily bloom lasts only one day. Hence, the name from the Greek, meaning beauty for a day. Not all blooms on a given stalk (called a scape) bloom the same day. Daylilies often send up one bloom stalk per fan. Thus, a clump of multiple fans will also usually produce multiple bloom stalks, and each stalk has multiple blooms. Therefore, an individual clump can produce many blooms in total. And because all buds do not bloom on the same day, the plant gives the illusion that the same blooms last for days, even weeks. However, it is simply a different batch of blooms each day, with a single plant having at least some bloom every day generally over a period of 2 to 3 weeks.

There are many different varieties of daylilies displaying different characteristics. We call each unique variety a 'cultivar.'

Daylily leaves are long and slender. They are varying shades of green. A few ones may show variegation. Yellow indicates trouble: disease or insect infestation.

The size of daylily blooms ranges from 1.5 inches (miniatures) to 8 inches or more (the spider varieties). The most common size is 5 to 6 inches.

Daylilies are hybrids. This means that, unlike some other plants, the seeds will not produce exact copies of the mother plant. Thus, you cannot use seed as a means of duplicating your favorite cultivars. As in humans, when you cross two parents, the offspring will exhibit traits of both, but the children will be unique and may even look unlike either parent.

Therefore, unless you are intentionally hybridizing, do not let seed pods remain on the scape. You would not be using the seed, and the growth of the pod will needlessly steal energy that could be better used to produce more blooms or new fan growth.

A CULTIVAR is a unique variety that has been named and registered with the American Hemerocallis Society (AHS). A variety is unique, just as people are, if it varies in any way from another plant. There are over 40,000 cultivars registered by name with the AHS.

The CROWN is the base of the plant at ground level, where leaves and roots join.


PETALS - foremost (normally three per flower) &
SEPALS - partially or totally hidden behind the petals (also normally three per flower bloom)
PISTIL (receives the pollen and transports to ovary at its base; one per flower)
STAMEN (Contains dust-like yellow pollen at its tip. Normally, six per flower. )

The SCAPE is the stalk on which flowers develop.

RECURVED means the ends of the petal and sepal segments roll or tuck under.


The leaves of Dormant (often signified with solely a 'D' in catalog listings) plants die back to the ground during winter. This is normal and does not indicate the plant is dead or sick. Evergreen ("EV") cultivars try to grow year-round. They succeed in the South, but in the North, the leaves look 'sickly' during winter where temperatures often fall below freezing. They don't die, but their new growth is continually ruined by freezing temperatures. They simply keep trying to grow but cannot do so. This is normal and does not impair the health of the plant.

Semi-evergreen ("SEV") plants lie somewhere in between. In fact, although all plants are categorized with one of these three labels, there are no clear breaks between one category and the other, because it is simply a gradual continuum from one extreme to the other. In fact, the same plant may exhibit different characteristics in different climates.

Generally, evergreen daylilies can withstand northern climates, but some dormant varieties may gradually die out in the deep South, because they need the rest of winter dormancy to flourish.

Note: in the North, although an EV may be hardy and thrive, it looks poor during winter and early spring. DOR plants, however, look great as they emerge from the ground in spring. Although the EV in the following picture looks ill, that condition is normal, and once freezes cease to impede it in late spring, it jumps to life, too, and you soon will not be able to distinguish an EV from a DOR.

Although there may be an occasional correlation between dormancy and hardiness and between evergreen and tenderness, too many daylily gardeners incorrectly use the terms interchangeably. In fact, an evergreen variety can be extremely hardy and perhaps even a dormant one tender. Plants are officially labeled as to dormancy by their hybridizers, hardiness is often not known at the time of registration and is not officially registered.

Without registered information with regard to hardiness, unless you find out from other gardeners or see it already growing in your region, the farther north you live, the greater the risk you take with regard to a specific cultivar. Another option is to research a cultivar's parents for some indication of what it might be like. An extreme generalization for northern gardeners would be to buy only those new cultivars which have been introduced by breeders who live in your region or a colder one. But this is an unnecessary precaution in my opinion. While it is true that most daylilies introduced in the North will be hardy, most Southern-grown varieties are also hardy. I have as many Evergreen daylilies in my garden as I do Dormant daylilies. (With many Semi-Evergreens, too, of course.)

REBLOOM most commonly refers to bloom scapes which appear later on in the same year, on the same plant, but after the initial flush of normal bloom. A period with no bloom can occur in-between normal bloom and rebloom, or rebloom can occur immediately after the normal bloom period is over. Rebloom simply applies to the subsequent appearance of more than one scape on the same plant. Rebloom is never as floriferous as the original bloom, but the plant's bloom cycle is extended, and the trait is desirable.


There are two sets of chromosomes, totaling 22 for diploids and four sets, totaling 44 for tetraploids. The terms Diploid ("dip") and Tetraploid ("tet") merely refer to the number of pairs of chromosomes.

All plants and animals have a basic complement of chromosomes, small bodies within the cell nucleus which carry genetic factors. Most plants are diploid; that is, they have two identical sets of chromosomes in each cell. A Tetraploid is only one possibility among a whole series of polyploids. Tetraploidy can arise from sudden cold or heat, or it can be the result of the union of unreduced cells during sexual reproduction. Such spontaneous chromosome doubling occurs occasionally in nature. Also, it can be induced artificially through the use of chemicals, that is, with a mutagen called colchicine (obtained from the autumn crocus "colchicum").

"Dips" are often said to be more refined, graceful, and versatile (for example, more color possibilities). "Tets" may tend to be more robust, larger, may have more intense and varied flower colors, have thicker flower parts, but are harder to hybridize as the temperature rises and are somewhat still limited in form, shape and color possibilities (at least for now). Many believe Tets are the wave of the future, because their greater genetic complexity should, in the long run make for a more variable and versatile flower. But many believe that hybridizing advancements come quicker in dips and continue to work with them. Both abound and a friendly debate persists over which is "better." (When hybridizing, you generally cannot cross a tet with a dip.) The average home gardener should ignore a cultivar's ploidy and not use this characteristic as a criteria for plant purchase.


Avoid relying solely on how pretty the flower is. Consider other plant characteristics too:

  • Branching (multiple is good, because it yields more blooms)
  • Bud Count (the more, the better)
  • Attractive Foliage (there's a lot of it-- it better look good)
  • Reblooms (or Not) -- obviously a reblooming plant yields more flowers
  • Fertile (or Not) -- relevant for hybridizing purposes only
  • Scapes that hold flowers at a good relative height -- above the top of the foliage
  • Scapes that do not lay down (if it requires a stake, get rid of it.)
  • ... simply strive for parts that are in balance with one another.

"CONVERTED" or "Treated" (with Colchicine)

With the chemical Colchicine (potentially dangerous and not generally available), it is possible, with some difficulty, to alter the course of a dip and convert it into a tet. This is a complex subject too lengthy to cover here.



diagram of the parts of a daylily plant
Click on image to see a larger copy.





picture of an evergreen daylily
an evergreen daylily in early spring


picture of a dormant daylily
a dormant daylily in early spring





comparison of a dip converted to a tet

This image shows the exact same cultivar, except that the flower on the left is from the original DIPLOID plant, and the one on the right is from the successfully converted TETRAPLOID plant. (Thanks to Dan Trimmer)

Not every conversion produces a tet version that looks better or is bigger than the dip version.