Botany Of Daylilies
Daylilies belong to the genus Hemerocallis and all of them are monocotyledons. Daylily plants have a tendency to form dense clumps. These are perennially growing plants and occasionally, they have rhizomes. At times, daylilies form leaf mounds and branched scapes appear from them. These scapes bear lily-like flowers resembling the shape of trumpets. While the flowering season of daylilies is fairly long, extending from the beginning to the end of summer, each daylily flower remains open only for one day. The color of the original daylily species is restricted to orange, yellow and fulvous shades, but the several thousand hybrids developed from them over a period of nearly 75 years come in an assortment of hues.
When we talk about a plant’s crown, we denote the intersection point from where its leaves, flowers as well as roots start growing. In case the crown is damaged, it will result in the death of some parts of the plant or the entire plant. The crown should be planted in a manner so that it remains buried about 1 cm (half inch) beneath the level of the soil. In fact, the frost hardiness of daylilies is dependent on the plants’ crown as well as the growth buds that overwinter on the crown.
The root system
Daylily roots emerge directly from the plant’s crown. Usually, the roots of this plant have a tan-brown hue and are dense, frequently having fleshy distensions. However, some daylily plants also have fibrous root system. The roots emerge from the sides of the crown and start growing downwards and outwards may be tapered or forked, akin to a crab’s claw. At the same time, the roots of daylilies may also be cylindrical, like in the case of H. dumorteiri, or shaped like a spindle as in the instance of H. fulva. On the other hand, the roots of H. middendorffii and H. lilioasphodelus are comparatively fibrous. Usually, daylily roots form thick and dense clumps. However, H. fulva and H. lilioasphodelus enlarge without restraints by means of rhizomes. The character of the daylily hybrids is possibly intermediate.
The distended parts on daylily roots serve as food reserves and help the plant to survive through its dormancy phase. They are also responsible for the plant’s robust growth quite early in spring compared to other plants that compete with daylilies.
Daylilies produce strap-shaped leaves, may vary from smooth to delicately grooved, generally, fairly creased inwards the length of the midrib and emerge from the crown in two arrangements. The leaves of daylilies curve outwards and upwards, as they arise to assume the shape of a fan. Daylily leaves are found in a variety of colors ranging from light to deep green, while some may even have a glaucous bloom. During spring, their color changes to yellowish to very light green. On the other hand, they sometimes assume rich yellow shades as well as ochres during autumn.
It is worth mentioning here that a warm climate daylily species H. aurantiaca is the only evergreen variety, while the remaining are all winter dominant to some extent.
The flower scapes
Daylily flowers appear on oblique or erect scapes or leafless stems that are usually firm. These scapes emerge right from the plant’s leaf fan. The scapes are smooth and hollow and their color may vary from light green to nearly black, like in the case of the variety called “Sir Blackstem”. These scapes are usually 5 cm (2 inches) in width, like in the case of the variety called “Scapes from Hell”. On the other hand, they may also be delicately thin, as in the case of “Kindly Light”.
Even the height of the scapes may differ – while some may be as small as just 4 cm (1 1/2 inches), as in the instance of H. darrowiana, there may be others that grow up to a height of 2 meters (6 feet), as in the case of H. altissima. In the case of hybrid daylilies, the height of the scapes varies from 22 cm to 115 cm (9 inches to 45 inches). On average the scapes of hybrid daylilies grow up to a height of anything between 45 cm and 75 cm (18 inches and 30 inches), while some scapes may reach 1.2 meters (4 feet), especially in a few of those belonging to Unusual Forms.
The scapes of daylilies have an approximately round cross-section and very scarcely branched in their portion. While the scape of the species H. multiflora does not have any branch at all, those of the H. middendorffi and H. dumortieri have branches, but only close to their tips. On the other hand, the scapes of another daylily species H. nana are unbranched and only one flower blooms on each scape. When the daylily is transplanted or divided, normally the scapes will be significantly lesser in height compared to what they will register in the subsequent season.
At times, proliferations of daylilies can give rise to scapes that grow up to a height of anything between 10 cm and 12 cm (4 inches and 5 inches) and will produce their own blooms even while remaining connected with their parent plant. “Double Cutie” and “Yesterday’s Memories” are an ideal example of this. This phenomenon is more likely to occur with daylilies grown in places having hot climatic conditions.
The bracts of daylilies are positioned on the upper one-third part of the scape. Usually, the bracts are held just under the base of every branch. However, at times they may also appear as somewhat node-like distensions on the scape. The bracts of this species bear resemblance to small and slender leaves. They have an stretched out oval shape that extends to a point lifted the length of the midrib and their color may differ from light green to deep brownish-black. The bracts of daylilies generally shrink and wither after flowering.
The flower buds
The flowering buds of daylilies initially appear small and nearly round in shape. They become elongated gradually till they achieve their utmost length on opening. At the same time, the flower buds also swell gradually on top of the tube. All the while, the tip remains pinched together and is somewhat creased on its external surface.
The color of the flower buds may vary from pale green to mahogany-brown, as in the case of H. dumortieri. While an anthesis draws near, the buds get their final color – that of the sepals. However, their color remains flushed green till they open fully, especially near the tip.
Nearly all species and cultivars of daylilies produce large as well as colourful flowers. A short pedicel attaches the flower to the scape. Each daylily flower comprises six segments similar to petals, which are collectively called tepals. These tepals are displayed in two sets of three – the external tepals that originally form the covering for the flower buds is known as sepals, while the inner tepals are called petals. Compared to the petals, the sepals are generally slender as well as more pointed. The sepals and petals are generally fused at the base of the flower forming a small tube like structure, which is also known as the throat. The outline of the perianth is roughly trumpet shaped, only flaring somewhat in the daylily species as well as the hybrids developed in the early days. On the contrary, the perianth is generally sharply recurving or rolling back in the contemporary daylily hybrids.
The reproductive parts of daylilies emerge from the tube or the throat at the base of the flowers. They include six thin stamens. The anthers that produce pollens – the male reproductive means, dangle at the tip of the stamens. The female reproductive organ called the pistil is in the form of a solitary tube somewhat broad and overhanging above the stamens. The pistil rises from the midst of the six stamens and the end that is connected with the flower is distended and the ovules are contained in this swollen part. The other end of the pistil that rises above the stamens is a little swollen and is called the stigma. When the stigma is receptive, it becomes muggy so that the pollens that come in contact with it stick there. Fertilization occurs when the pollen passes down through the tube into the pistil to come in contact with the ovules. The flowers fade and drop to the ground following fertilization, leaving behind the ovary capsules. It takes about 60 days to 80 days for the ovary capsule to ripen and throw out the seeds.
Many daylily species are aromatic and are classified as heavy or musk and their fragrance is comparable to that of honeysuckle. In fact, the aroma of H. lilioasphodelus is said to be the most potent and the fragrance of H. citrina as well as H. thunbergii come very close to it. Even the flowers of other daylilies such as the H. middendorffi, H. altissima, H. minor and H. dumortieri are somewhat fragrant. Humidity as well as moisture plays a vital part for daylilies to exude fragrance. While the aroma of nocturnal daylilies is evident when the flowers open up, in the case of fragrant diurnal daylilies, the aroma is not exuded until the day becomes warm. Most daylilies grown in places having cool climatic conditions are far less aromatic compared to those grown in the climatic conditions similar to their native habitat.
The seeds of daylilies develop inside the somewhat egg-shaped deep green hued ovary capsules each of which comprise six segments that are divided by six ribs. The ripened segments of the ovary capsule spring open usually in pairs after fertilization, which usually takes anything between 60 and 80 days. You can see three rows of ovoid or round seeds in each segment after they open up. Each of these ovoid seeds has a somewhat elevated point at any one end. If the seeds are black and glossy it indicates that they are fertile. On the other hand, white seeds signify that they are sterile. Seed capsules of different daylily species and cultivars enclose different number of seeds. In fact, the tetraploids always contain the lowest number of seeds.