Frequently Asked Questions about Daylilies

The following daylily questions and answers have been summarized from The Illustrated Guide to Daylilies, a publication of the American Hemerocallis Society (AHS). Also, check out the AHS Daylily Dictionary for additional material on many of the topics below:

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What is a daylily?

The scientific name for daylily is Hemerocallis, most recently considered to belong in the plant family Hemerocallidaceae. Previously, many older works placed daylilies in the Lily family, Liliaceae. Notice that the preferred spelling is "daylily" as one word. Many dictionaries spell it as two words. The word Hemerocallis is derived from two Greek words meaning "beauty" and "day," referring to the fact that each flower lasts only one day. To make up for this, there are many flower buds on each daylily flower stalk, and many stalks in each clump of plants, so, the flowering period of a clump is usually several weeks long. And, many cultivars have more than one flowering period.

Why is the daylily the perfect perennial?

The daylily is sometimes referred to as the perfect perennial because it is:

Available in a rainbow of colors and a variety of shapes and sizes.
Able to survive with very little care in a wide range of climates.
Suitable for all types of landscapes.
Drought tolerant when necessary, with relatively few pest and disease problems in most gardens. See descriptions of pests and diseases that may be encountered .
Adaptable to various soil and light conditions.
Known to bloom from late spring until autumn.

Where did daylilies originate?

The genus Hemerocallis is native to Asia. Since the early 1930s, hybridizers in the United States and England have made great improvements in daylilies. Originally, the only colors were yellow, orange, and fulvous red. Today, we have colors ranging from near-whites, pastels, yellows, oranges, pinks, vivid reds, crimson, purple, nearly true-blue, and fabulous blends. Many people are familiar with only the common yellow or orange daylilies which are often seen along roadsides. These daylilies are cultivated forms of the wild types of daylilies which have "escaped" and are growing as if they are wild. All the modern daylilies have been developed through a complicated history of hybridization among these and other wild types.

What are the parts of a daylily?

The daylily can be characterized as a clump-forming, herbaceous perennial with fibrous or somewhat tuberous roots. The daylily has four fairly distinct growing parts.

Roots: The roots of a daylily are long, slender, and fibrous. Or, they may be enlarged into spindle-shaped tubers with additional roots at their bases. The roots absorb water and minerals for use by the plant, and serve as storehouses for food produced by the leaves.
Crown: The crown of a daylily is the stem of the daylily plant. It is the solid white core located between the leaves and the roots. The crown produces leaves and scapes from its upper surface. The roots are produced from its sides and lower surface.
Leaves: The leaves of daylilies are long, slender, and grass-like. They have a prominent center rib on the underside. The leaves are arranged opposite each other on the crown, giving a flattened appearance which causes the plant to be referred to as a "fan." Multiple fans of a single plant form a "clump."
Scape: The scape of a daylily is a leafless stalk which bears the flowers. Most have two or more branches, each bearing several flower buds. Below the branches, the stalks have a few leaf-like "bracts." Sometimes, a small plantlet grows at the junction of a bract and the scape. This is called a "proliferation" and can be rooted to produce another plant.
: See also the Daylily Dictionary Parts of a Daylily Image Map - just click on the terms.

What are the flower colors of daylilies?

Modern hybrid daylilies have a remarkably diverse color range, especially considering that the wild types from which they have been bred were only in shades of yellow, orange, fulvous (i.e., dull reddish yellow), and rosy-fulvous. Today, the only colors notably lacking are pure white and pure blue. Needless to say, hybridizers are avidly pursuing these two colors.

Basic Flower Color

The outer portion of the daylily flower is considered to be the basic color of the flower. The present daylily color range includes:

Yellowall shades from the palest lemon, through bright yellow and gold, to orange.
Reddiverse shades of scarlet, carmine, tomato-red, maroon, wine-reds, and blackish-reds.
Pinkfrom pale pink through rose-pink to rose-red.
Purplefrom pale lavender and lilac to deep grape or violet.
Melon or Cream-Pinkfrom palest cream shades to deep cantaloupe shades.

Notes: Buff, Brown, Apricot, and Peach are thought to be variations of pink plus yellow. Near-whites are found among the palest tints of yellow, pink, lavender, or melon.

Throat Color

The center area of the daylily flower is called the throat. In most daylilies, the throat color differs from the rest of the flower. Usually it is a shade of green, yellow, gold, orange, apricot, or melon.

Stamen Color

Like the throat, the stamens may be a different color from the basic flower color and the throat color. Or, the stamens may be of matching color. Usually they are light yellow to greenish. The anthers at the tips of the stamens are often darker in color

sometimes black.

What color patterns are found in daylily flowers?

Most of the following terms are illustrated in the Daylily Dictionary - just follow the links. Modern daylilies display a complex variety of color patterns that were unknown in the original wild types. The patterns include:

Self

The simplest pattern in which the flower segments (i.e., petals and sepals) are all the same color (e.g., pink and rose). The stamens and throat may be different.

Blend

The flower segments (i.e., petals and sepals) are a blend of two or more colors. The stamens and throat may be different.

Polychrome

The flower segments have an intermingling of three or more colors (e.g., yellow, melon, pink, and lavender). The stamens and throat may be different.

Bitone

The petals and sepals differ in shade or intensity of the same basic color. The petals are the darker shade (e.g., rose pink), while the sepals are lighter (e.g., pale pink). A Reverse Bitone has sepals which are darker than the petals.

Bicolor

The petals and sepals are of different colors (e.g., red and yellow or purple and gold). The petals are the darker of the two colors. A Reverse Bicolor has sepals which are darker than the petals.

Eyed or Banded

The flower has a zone of different color or a darker shade of the same color located between the throat and the tips of the flower segments.

It is an Eye if the zone occurs on both the petals and the sepals.
It is a Band if the zone occurs only on the petals.
It is a Halo if the zone is faint or only lightly visible.
It is a Watermark if the zone is a lighter shade that the rest of the flower segments.

Edged or Picoteed

On some daylilies, the edges of the flower segments are either lighter or darker than the segment color. The width of the edge can range from a very narrow "wire-edge" to as much as 1/4 to 1/2 inches.

Tipped

The segment tips, or more frequently just the petal tips, are a different or contrasting color from the body of the segment (sometimes for as much as one third of the length).

Dotted, Dusted

The surface color of the flower appears to be unevenly distributed over the background color of the bloom rather than being smoothly applied.

It is Dusted if the color appears to be finely misted onto the surface.
It is Dotted if the colors are clumped into larger pools.
Other terms used to describe uneven coloration include: Flecked, Flaked, Speckled, and Stippled.

Midrib

This is the center vein running lengthwise through each flower segment. In some cultivars, the midrib is different in color from the rest of the segment. The midrib can be flush with the surface, raised above it, or recessed.

Diamond Dusting

Tiny crystals in the flower's cells reflect light, especially in the sun, to give the flower a sparkling or glistening appearance as if sprinkled with gold, silver, or tiny diamonds.

What flower forms are found in daylilies?

Daylily blooms have a wide array of different forms. These include:

Circular

When viewed from the front of the bloom, the flower appears round. Segments tend to be short, wide, and stubby and generally overlap, giving a full appearance.

Triangular

When viewed from the front of the bloom, the flower segments form a triangle. The sepals generally recurve.

Star

When viewed from the front of the bloom, the flower segments tend to be long and pointed. There is space between the segments and the shape looks like a three-pointed or six-pointed star.

Informal

When viewed from the front of the bloom, the flower segments have no definable shape. Segment placement may be irregular, widely-spaced, or floppy.

Ruffled

When viewed from the front of the bloom, the flower segments have ruffles along the edges. Ruffles take many forms; they may be tightly crimped, laced, knobby, or wavy.

Flat

When viewed from the side of the bloom, the flowers are perfectly flat except for the concave throat.

Recurved

When viewed from the side of the bloom, the flower segments flare, but the ends of the segments roll or tuck under.

Trumpet

When viewed from the side of the bloom, the flower form resembles a true lily. Segments rise from the throat in an upward pattern with little flare.

Spider

This form has long defied definition, however the segments are much longer than their width.

A 1991 ruling places flowers in the spider class if their segments have a length to width ratio of at least 4 to 1 (i.e., 4:1).
Length is measured with the segment fully extended. Width measurement is taken as the flower grows naturally.

Double

This form has more than six segments. Double daylilies, like single daylilies, come in differing forms. For example:

The extra segments may appear as a tuft in the middle of the flower. This if often referred to as a "peony-type" double.
They may appear as a second layer of segments on top of the normal six, forming two blooms in one or a hose-in-hose effect (like some azaleas).
They may appear as irregular or asymmetrical extra petaloids.

What other characteristics are used in describing daylilies?

Other characteristics often used in describing daylilies include:

Texture

Texture refers to the surface quality of the tissue structure of the daylily bloom. There are three main types of texture in daylilies

smooth, creped, and ribbed.

Substance

Substance is the thickness of tissue structure, or the ability of the flower to withstand the elements. Substance varies from delicate (i.e., a thin, fragile appearance, but still durable) to heavy and leathery.

Size

There are three categories of bloom size in daylilies:

Miniature. Flowers that are under 3 inches in diameter.
Small. Flowers that are from 3 inches up to 4 1/2 inches in diameter.
Large. Flowers that have blooms 4 1/2 inches and over in diameter.

Height

Flower scapes 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.

Branching

Daylily scapes with no branching have slender shoots with a cluster of buds at the top. Branching allows one scape to bear from 10 to 100 buds. Branching may be described as multiple (i.e., a number of side branches) or "three-way" with the "three" (or other appropriate figure) indicating the number of branches per scape. There are three types of branching:

Top Branched, where the branching occurs only near the top of the scape.
Well Branched, where the branching begins near the top of the foliage.
Low Branched, where the branching extends into the foliage.

Blooming Habits

Most daylilies bloom for a single day, beginning in the early morning and lasting until the evening. There are three terms necessary to describe the normal and the atypical bloom habits found in daylilies:

Diurnal, which is the normal day-blooming daylily type.
Nocturnal, where daylilies open late in the afternoon, remain open all night, and close the following morning or early afternoon.
Extended, where individual daylily blooms remain open at least 16 hours. Both diurnals and nocturnals may be extended bloomers.

Blooming Sequence

Daylilies bloom from early spring until frost, depending on the coldness of the climate. To indicate when a particular cultivar blooms during the season, daylily growers use the following terms and abbreviations (or symbols):

Extra Early (EE). These daylilies are the first to bloom, and vary from March or April in the extreme South, to May or June in the North.
Early (E). These daylilies bloom three to five weeks prior to the mass of bloom at midseason.
Early Midseason (EM). These daylilies bloom one to three weeks before the height of bloom of most cultivars.
Midseason (M). These daylilies bloom at the peak of the daylily bloom in your own garden. This ranges from May in the South to July in the North.
Late Midseason (LM). These daylilies bloom one to three weeks after the height or peak of bloom in your garden.
Late (L). These daylilies bloom when most others have finished blooming, usually four to six weeks after the peak of the season.
Very Late (VL). These daylilies are the last to bloom, often late in the summer in the South, fall in the North.
Rebloomer (Re). These daylilies bloom more than one time during a single season. Some of these bloom early (e.g., May or June) and then repeat in the fall. Others have a succession of bloom periods, one shortly after another for several months.

What are the foliage traits of daylilies?

Foliage traits of daylilies include color, size, habit, and cold-hardiness and heat-tolerance.

Color

The foliage of daylilies can be blue-green to yellow-green or any shade in between.

Size

Daylily leaves vary considerably from slender and grass-like to husky, wide, and nearly corn-like. The leaves may arch, or may stand nearly erect. The length of daylily leaves ranges from as little as 6 inches to 36 inches or more.

Habit

The winter behavior of the daylily foliage is called "the foliage habit." For registration purposes, the foliage habit is loosely categorized as dormant, evergreen, and semi-evergreen.

Dormant. The leaves of these daylilies die completely back as winter approaches. They stop growing and form resting buds at the crown, and the foliage dies down naturally and gradually. In the spring, the resting buds have a distinctive spear-like appearance as they emerge.
Evergreen. These daylilies retain their leaves throughout the year. They do not form resting buds. Instead, they continually produce new leaves unless cold weather prevents growth. In mild climates, the leaves of evergreens remain green all winter. In the coldest climates, the foliage of evergreens nearly always is frozen back, but the crown survives if it is hardy (or well mulched).
Semi-Evergreen. Today, the term semi-evergreen is used to describe any foliage behavior which is not readily classed as simple evergreen or dormant. Originally, the term semi-evergreen (or conversely, semi-dormant) was used to describe those daylilies which retained many of its leaves and appeared somewhat evergreen when grown in the South, but lost all its leaves and went dormant when grown in the North.

Cold-Hardiness and Heat-Tolerance

The cold-hardiness of daylilies is quite variable. Some are iron-clad hardy. Others are extremely tender. Cold-hardiness is not determined by the foliage habit. Evergreen, dormant, and semi-evergreen can be anything from extremely cold-hardy to extremely tender. To avoid risk of losing a cultivar, choose daylilies which others have already grown successfully in your climate.

What is the difference between diploid and tetraploid daylilies?

Plants all have a basic complement of chromosomes. Most plants are diploid

they have two identical sets of chromosomes in each cell. Polyploids are plants with more than two sets of chromosomes. A tetraploid is only one of a whole series of polyploids. Triploids have three sets of chromosomes, tetraploids have four sets of chromosomes, et cetera.

Tetraploid
Tetraploid daylilies are heralded by some growers as having a number of advantages over diploids. In the tetraploid:

Flowers tend to be larger.
Colors of the flower tend to be more intense.
Scapes tend to be sturdier and stronger.
Substance of both flower and foliage tend to be heavier.
Vegetative vigor in leaf, stem, and flower tend to be greater.
Breeding possibilities tend to be greater because of an increased number of chromosomes

Diploid

Diploid daylilies continue to charm growers with their exquisite flower form, grace, and color.

Good pink daylilies are still more prevalent in the diploid ranks.
Spider and double daylilies are still more prevalent in the diploid ranks.
Diploid daylilies are easier to cross than tetraploids.
Many diploid daylilies have been converted to tetraploids, thus advancing the tetraploid lines.
There are more diploids than tetraploids.

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