Cultivation Of Daylilies

Daylilies are among the easiest of perennials to grow, provided their few essential requirements are met. However, difficulties may be experienced with some of the more inbred cultivars, especially those with complicated color patterns and heavy edge embellishments, if they are grown in climates very different from the ones in which they were bred. That said, most daylilies will fit seamlessly into the average garden provided they are given a place in the sun and a fertile soil.

Soil

Daylilies grow best in well-drained, but moist, rich, friable loam, cultivated to a depth of about 45-60cm (18-24in). Best with a pH of about 6, they can also be grown successfully in soils well to either side of neutral, and will tolerate chalk, heavy clay or loose, sandy conditions, provided that generous supplies of organic material are incorporated into the soil and used as a mulch.

Heavy clay is the soil daylilies least like as it is usually very badly drained which could cause rotting. Drainage can be improved by adding copious amounts of coarse grit and organic manure, preferably in equal quantities by volume. In severely heavy soils land drains may be needed. An alternative strategy, used by many growers, is to plant daylilies in raised beds filled with imported top soil or compost.

Once loosened and rendered free -draining, a clay soil can be the ideal medium for daylilies since it is usually high in nutrients. Sandy soils are free-draining but the nutrients will quickly leach out. Like clay, sandy soils improve vastly with the addition of generous amounts of organic matter which helps to make it more water retentive. Regular mulching and extra nutrients are necessary, augmented by foliar feeds in early spring and as the buds are forming.

Planting

Daylilies can be planted at almost any time of the year, provided the ground is open, but local conditions may make a particular season preferable. Many growers recommend spring planting, especially in cold-winter areas since the plants will then have the summer weather during which to become established, making good roots before winter. Most growers in areas with severe winters keep autumn delivered daylilies in a greenhouse through winter. By late spring, when they are planted in the garden, they will already have produced flowers, seeds and scape increases and will often rebloom. Cultivation in the high temperatures of a greenhouse may produce uncharacteristic doubling of some daylilies, such as 'Elizabeth Salter'.

Other growers prefer autumn planting since the soil, having been heated by the sun all summer, will be warm, enabling the plants to make more rapid root growth. Most roots grow in soil temperatures of 2-18°C (35°F-65°F) and stop after 18°C (65°F). Generally speaking roots are happy at 8°C (15°F) less than the above ground parts of the plant. However, the roots of newly planted daylilies grow faster if their water requirements are met.

Autumn planting should be carried out at least six weeks before the predicted onset of frosts. Those daylilies that were in summer dormancy will make a spurt of growth in late summer and early autumn provided they have moisture, but it is not a good idea to plant evergreens recently received from hotter climates in the autumn. They should be potted until warmer weather returns. In the hottest regions, planting can be delayed until mid-autumn as there will be no fear of heavy frosts.

Planting is not recommended on hot summer days, but if unavoidable, the newly planted daylilies should be shielded from the direct rays of the sun.

A spacing of 60-90cm (2-3ft) is ideal if the daylilies are to remain in the same position for a number of years. If an immediate display of color is required plant about 45cm(18in) apart: daylilies planted this close will require earlier division.

The planting hole should be at least twice as large as the roots to be planted and never less than 45cm (18in) across by 23cm (9in) deep. The soil should be dug out and the bottom of the planting hole thoroughly broken up. Plenty of garden compost or farmyard manure should be incorporated into the soil before it is returned to the hole. This will provide all the immediate nitrogen (N) requirements. A fertilizer high in phosphorus and potassium (P, K) should also be added and will be taken up slowly by the daylily. Nitrogen moves through the soil more quickly so needs to be added more frequently.

The roots of most daylilies grow outwards and downwards leaving an area without roots immediately below the crown, so a small mound of soil should be left in the centre of the planting hole, to fill up this rootless space. Having positioned the daylily on the mound, firm the soil around the roots. If the daylily has become pot bound, its roots will need teasing out so that they are free to spread out over the mound of soil. Remove any dead or damaged roots at this time. The crown should be planted at the same level as that from whence it came, just deep enough to cover the non-green portion of the fan, not deeper than 2.5cm (1 in) in areas that have snow cover, or it may not bloom. Refill the hole with garden soil mixed with a potting mix. Make sure the soil mound is well tamped down before planting because if the crown sinks too low it may die.

If plants arrive with newly forming scapes, these should be cut off so that all the plant's energy goes into production of a healthy and vigorous root system. If new scapes appear about 2 months after planting keep just one so that the identity of the plant can be verified. Daylilies that are transplanted during reproductive or bloom periods may need some time before resuming active growth, but if transplanted just before or during their growing season, they will not take so long to establish. In any case it can take up to three years before plants exhibit their full potential.

Care of daylilies

Mulching and feeding

Mulching can supply day lilies with extra nutrients but far more important is the mulch's ability to hold moisture, thus moderating the extremes of wetness and dryness in the soil. Moreover, as the mulch decays it turns to humus, which vastly improves the soil structure. The best types of mulch are garden compost, farmyard manure or mushroom compost but other materials such as shredded bark, pine straw or leaves can also be used.
Well-rotted manures and garden compost are best applied after the foliage of dormant day lilies has died down and in time for autumn rains to water it into the ground. Dehydrated manures can be applied in autumn or spring as they are quicker acting. They are also easier to handle, are quite safe to use directly from the packet or container, but are highly concentrated and should be applied sparingly. Organic material from a garden compost heap can never be applied too often as it helps to build up the structure of the soil on a permanent basis in the way that artificial fertilizers never can.
A mulch for permanent cover and soil enrichment should be applied in a layer approximately 5-7 cm (2-3in) thick. If it is for protecting somewhat tender evergreens in cold-winter areas, it needs to be anything up to 30cm (12in) deep and must be removed in spring to prevent the emerging shoots from being smothered. The use of leaf mould, however beneficial to the friability of the soil, has the disadvantage of significantly increasing the slug population. In some parts of the United States leaf mould can also encourage southern stem blight (Sclerotium rolfsii).
Feeding is necessary not only to produce the best flowers but also to nourish the root system, thus enabling the plant to increase well and remain in the best of health. Before applying nutrients other than garden compost or farmyard manure, it is advisable to have the soil checked for deficiencies. There might be only one element lacking, but to grow daylilies successfully a combination of many ingredients is necessary, so having the soil tested is well worth the time and expense. Soils differ widely so one type of balanced food is not necessarily the best for all soils, though generally it will be adequate.
For a temporary boost, apply high-potash fertilizer as a foliar feed, including a few drops of soap to act as a surfactant. This can help to keep a daylily flowering at its maximum potential and also benefits the foliage, although overdoing it could eventually poison the soil. Tomato foods also help to boost daylily flower production. High-nitrogen fertilizer, which can improve the foliage early in the season, should not be applied after midsummer since it can make new growth soft and more susceptible to insect damage.
Other soil ameliorants such as alfalfa pellets, which contain enzymes that help to unlock the nutrients in fertilizers, are much used in the United States. Many growers, including some leading hybridizers, also add sewage sludge. This contains magnesium which helps to enhance the near-blue effect in flower colors and gives the foliage a good color. Epsom Salts (magnesium sulphate) has the same effect. It can be used at the rate of 3 tablespoons of crystals per gallon of water and must be applied in solution only. Its overuse over a prolonged period may make the soil too acid for daylilies and can also lead to a build-up of salt. Lime can help remedy acidity.

Watering

Water is even more important to the health of daylilies than feeding, since without adequate water the nutrients cannot be taken up. Some growers water only at planting time or in times of severe drought, the theory being that daylilies are only worth having if they can adapt themselves to the prevailing conditions. However, without sufficient water the plant looks limp, the foliage is a poor color, the flowers are sparser, poorer and of thinner substance, the length of the bloom period is affected and there is less or no rebloom in areas where there is a reblooming potential. While it is true that excessive over watering can cause daylilies to rot or die, they do require an abundant supply of water and will repay the grower with bigger, better and more colorful flowers and more and taller scapes with a higher bud count.
The best method of watering is either by leaky hoses, woven discreetly around the daylilies on the ground or by leaving a slowly trickling hose on the ground and moving it to a different area from time to time. As a general guide daylilies need 2.5cm (1 in) of water per week during summer (the equivalent of 18 liters/4 gals per sq m/yd). Daylilies growing in containers in full sun need watering twice a day. Most nurseries with large display gardens water with overhead spray lines, but this can adversely affect the following day's individual blooms, especially in daylilies having an abundance of buds that virtually touch each other. The spent blooms become soggy and, if resting against other buds, can destroy many future flowers unless individually removed by hand.

Positioning

Daylilies usually require about 6-7 hours of sun per day. In milder climates they should not be planted in shade; in very hot climates the darker shades of red, red-black, purple and purple-black are best planted to receive morning sun but afternoon shade, otherwise the top layer of pigment can melt, producing an unsightly greasy effect on the surface of the bloom. In hot climates the darker shades can also change color somewhat over the length of a day, but adequate watering gives them a better chance to overcome this problem.
Daylilies can tolerate windy conditions, making them ideal for coastal and for windswept areas. Newly planted daylilies in such conditions need some protection in the form of a windbreak until they are properly established.
Daylilies do best in conditions of high humidity with overcast skies which tend to make the colors richer; the colors are even richer in cooler climates but less flowers are produced. However, in cool climates, a sheltered place within a warm microclimate can help to ensure maximum flowering potential, particularly with tetraploids of heavy substance bred in hotter regions. All night street lighting within a proximity of 1.2m (4ft) will accelerate the bloom season. If possible plant on the sunny side of the house.

Grooming after blooming

Nothing spoils a floriferous clump of daylilies more than the presence of dead and dying blooms. Breeders are trying to produce self-cleaning daylilies, but have not yet been successful, so the removal of spent blooms by hand is still often necessary. Some people remove the spent blooms early each morning and this keeps them in touch with how the daylilies are performing; an even greater council of perfection is to deadhead them late in the evening, before the deadheads have liquified into a sticky mess. This also means that one is less likely to knock off those blooms in the process of opening.

Once a scape has finished flowering it looks unsightly, so unless the pods are to beset for hybridizing purposes, it should be removed, cutting it near the ground.

When flowering is finally over for the season, evergreen or semi-evergreen daylilies will just need to be tidied up until new foliage comes up in spring, when some of the old leaves can safely be removed. Decaying dormant foliage should be removed as soon as possible in order to leave the garden tidy for winter and prevent slugs and snails over-wintering in it.

Staining - Sap exuding from spent flowers can stain hands and clothing during the deadheading process. These stains can be removed from clothing by immediately soaking it in a strong detergent and rinsing well. It may take several attempts to remove the stain completely. Hands should be washed in any proprietary heavy-duty cleaner.

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