Author: Ing. Marketa Machackova
Daylilies are herbaceous plants growing in clumps. Strong fleshy roots grow from short rhizome out; sometimes they extend to a small tuber. Leaves form a rosette, are quite long and folded in half along midrib. Stem is branched and caries 1-6 flowers. Flowers have 6 petals turning into capsule.
There are two species growing in Europe, both of them probably introduced. They are Yellow Daylily (H. lilioasphodelus) which can be found in wild in Italy and Slovenia, and Orange Daylily (H. fulva) growing mostly near human inhabitations. Other botanical species come from South-east Asia like China, Korea, Siberia or Japan. They flower in yellow or orange color. There are about 20 species described: e.g. Citron Daylily also called Long Yellow Daylily (H. citrina), Dumortier’s or Dwarf Yellow Daylily (H. dumortieri), Small Daylily (H. minor), Amur Daylily (H. middendorfii) and Thunberg’s Daylily (H. thunbergii).
What comes in mind first are orange flowering lily-like plants from grandma’s garden. But they have been used for centuries in China as vegetables or medicinal plants for calming. All parts of the plant are edible: flowers for decorating salads, flower buds for cooking or young sprouts instead of green beans. Chinese pick flower buds of Citron Daylily (H. citrina) at sunset, when they open up, dry them and crush into powder used as flavoring in soups for a mild lemon flavor.
Daylilies were first mentioned in Chinese manuscriptt in 2697 B.C. At first they were cited just as medicinal plants and vegetables, decorative purposes appear much later. European introduction started with already mentioned Yellow Daylily (H. lilioasphodelus), later Orange Daylily (H. fulva) described by botanist Clusius in 1570. Its name Hemerocallis comes from Carl von Linne and his famous book Systema Naturae (1753) inspired by Greek “hemera“ = day and “kallos“ = beauty. Since first remarks on daylilies to the end of 19th century, botanist brought from Asia different native plants and garden variations e.g. H. fulva ‘Flore Pleno’ (introduced in 1869). These plants were gathered in botanic gardens where first intentional hybridizations started. The very first daylily cultivar ´Aprikot´ (Yeld, 1893) comes from England as a hybrid between H. lilioasphodelus a H. middendorfii. Or American ´Mikado´ (Stout, 1929) originated from New York Botanical Garden and its director Arlow B. Stout, who is considered the father of daylily hybridization. In 1934 he wrote a great monograph called simply “Daylilies”. Nowadays Stout Silver Medal is given in his honor every year as the highest award for the most beautiful daylily by American Hemerocallis Society. A very specific group are tetraploid cultivars of daylilies (4n=44). Their breeding started in the sixties of the last century because of more vigorous growth, more flowers and generally higher resistance compared to botanical species.Garden cultivars of daylilies are mostly results of breeding done in the last 70 years. From different botanical species, which flowers are only yellow or orange, endless variation of colors, shapes and sizes slowly appear.
Daylilies have many characteristics to observe and describe which manifestations of their gene pools are. One of them is dormancy (a rest period of the plants). Plants can be:
Dormant – they hibernate in winter when frost and new foliage appears in spring.
Semi evergreen – they don’t go dormant, foliage dries too, but it is actually frost damage.
Evergreen – these plants don’t need any rest period, they can grow all year around. In local climate, they get their leaves but also roosts frost damaged.
Another characteristic is height of the plant. They can be: dwarfs reach only 30cm as a small clump, growing from 30-60cm (low) to 60-90cm (medium) or exceeding 90cm and being called tall.
The most evaluated part of the plant is the flower. There are many characteristics of it:
Size - flowers can be miniature, smaller than 7,5cm or large, bigger than 11cm.
Flowers shape – it can be round, triangle, star shape or informal (cascade, crispate, spatulate), curled, undulated, flat, arched, trumpet shape, single or double.
Blooming season – main season is in July, compared to that cultivars can be early (3-4 weeks earlier) or late (flowering 4-6 weeks after mid-season. Some daylilies can rebloom.
Colors and color pattern - this is what is the most attention paid on flowers.
For better understanding, here is a table with pictures.