Daylily Terminology

Learn about the terminology of daylilies to better discuss and understand them! Browse the list below and feel free to ask us questions.


Bloom Size: The diameter of the open bloom.

Blooming Habit: Most daylilies bloom for a single day beginning in the morning and closing in the evening.

Diurnal Habit: Normal daylily blooming habit.

Extended Habit: The bloom remains open for at least 16 hours.

Nocturnal Habit: The bloom opens at night and remains open throughout the following day.

Scape: A leafless stem which carries the flowers.

Branching: The way buds form on their scapes. Well branched daylilies have a good balance of branches all along the scape rather than clustered at the end of the scape. There are buds in many stages of development on a well branched daylily, insuring a very long bloom period.

Height: Measured from the ground to the top of the scape when the daylily is in bloom.

Substance: Refers to the thickness of the tissue structure which determines the ability of the flower to stand up to the elements.

Bud Count: A daylily with a bud count of 25 will produce 25 blooms over the course of its bloom period.

Cold Hardiness: Foliage type does not determine hardiness. The best way to find daylilies that will be hardy in your garden is to buy them from a nursery who is field growing them in your area.

Color: No standard color chart exists. Thus, a daylily described as pink can range from creamy pink, through peachy pink, to old rose. Photographs don’t always help because colors vary with the type of film, light exposure and filters used.

Diamond Dusted: Appearance of having a layer of glitter on the bloom. This will be most visible on sunny days.

Eye, Halo: A bloom with distinct color markings just above the throat is referred to as having an eye. A less distinct marking is a halo.

Flower Form: There are five terms to describe the flower forms of daylilies.

Single Form: Consists of three petals, three sepals, six stamens, and one pistil.

Double Form: Double daylilies come in several forms. There are those that have extra layers of petals so they look like a flower within a flower, and those that look like peonies with extra tissue on the stamens inside the petal whorl.

Spider Form: A flower whose length to width measurement is at least 4:1.

Unusual Form: Daylilies have petals or sepals that are pinched, twisted, quilled, cascading, or spoon shaped.

Polymerous Form: Daylilies that may have extra sepals of petals.

Foliage Type: Daylilies are categorized into three divisions

Evergreen: This daylily holds its foliage until the ground freezes, and in warmer climates may remain green all year long.

Dormant: This daylily dies back to the ground each fall.

Semi-evergreen: This daylily is not clearly dormant or evergreen.

Rebloom: The tendency to have more than one cycle of flowering. Some daylilies bloom and then have another later season bloom, which is caused by culture, rainfall, soil fertility, and amount of sunlight.

Season: Bloom season begins with the first daylily that opens and the last daylily to bloom. Bloom season typically spans from the middle of June to the end of September.

Tetraploid: These daylilies carry twice as many chromosomes as usual (the usual number of chromosomes in a daylily is eleven pairs), causing them to have thicker petals, brighter colors, and robust foliage.