Cultivation Of The Lilies

The first and the last requirement for lilies is good drainage. The bulbs enjoy an open soil structure; they revel in humus but also relish a gritty component in their diet. Plants grow very fast through spring into summer; during this period they can make good use of copious draughts of water. Given this good start, they can then hold out against modest droughts although, as in nature, they are happiest with underground moisture in the absence of rainfall. In their wild homelands lilies may be without rain for months, but would be drinking the water derived from melting snows. In winter the bulbs will be unhappy to be standing long in stagnant water. Then, perhaps even more than at other times, happiness is sharp drainage.

Like clematises, lilies also like their heads in the sun and their toes in the shade. Beyond this, their specific needs or preferences are not onerous. Species such as L. speciosum and L. auratum regard lime as the arsenic of their world, a quick way to oblivion. Conversely, L. candidum likes rather than hates some lime but, in sole opposition to lily norms of behavior, needs its bulbs planted just under the soil's surface, quite un-lily like. L. martagon, L. monadelphum and some others, once settled in their domain, may be happy to stay put for the next hundred years or so, and may extend their territory by seedling-led accession if given the opportunity. On the other hand, pretty little L. pumilum or L. concolor are often short-lived as individual bulbs. They can seed themselves to extinction, but this seed germinates freely and new plants are soon blooming.

Humus and mulches

Humus is beneficial in encouraging acidity, aerating the soil, aiding drainage and helping to maintain healthy soil organisms. It also acts as a sponge to retain moisture. As a surface mulch it can repress weeds, conserve moisture and help to insulate the soil from excessive temperature fluctuations.

Leaf mould and well-made compost are equally welcomed by lilies. Mulches of dead bracken, dead leaves and similar material can be useful around the year. Fresh fronds of bracken, cut and shredded before they unfurl, make a potash-rich cover. Shredded bark looks attractive and also insulates, suppresses weeds and retains water while improving the soil structure. An 8-10cm (3-4in) thick mulch layer will last for around three years.

Site and soil

The single most important key to success in growing lilies is to provide a well-drained site. Lilies do not thrive for long where the soil is heavy and wet. Poor drainage is responsible for many of the losses frequently ascribed to other causes. If good under drainage is provided, most lily species and hybrids will grow well in many different types of soil.

Probably the most satisfactory soil for lilies is a deep sandy loam that is well aerated and allows water to pass through freely. The presence of clay soil, however, should not deter anyone from growing lilies. Clay soils are rich in nutrients and can produce strong, healthy lilies if the physical qualities of the soil are handled correctly.

A sloping site for a lily bed is an asset that should not be ignored, especially if the water can drain freely. On flat land, tile or other drainage systems can be installed to carry away excess water. Remember that just digging a deep hole or trench in heavy soil and putting rocks at the bottom does not necessarily provide good drainage: the water must be able to move away freely, otherwise such a trench becomes a sump, and a graveyard for lily bulbs.

When preparing a special bed for lilies, it is advantageous to raise the level of the bed above that of the surrounding area. This prevents undesirably high moisture levels in the top 15 to 25 centimeters (6 to 10 inches) of the soil. This raised-bed method has been used very successfully by commercial growers, who typically build the beds 120 centimeters (4 feet) wide and 15 to 20 centimeters (6 to 8 inches) high, with a 30-centimeter (1-foot) path between beds.

The addition of sharp sand, washed gravel, or crushed pumice opens heavier soils and improves the flow of water; unwashed crushed rock, however, must not be added to clay or it will form a concrete like mass. A similar benefit is obtained by adding coarse organic matter such as commercial compost or bark dust. The addition of lime also affects soil structure, causing the flocculation of soil particles and allowing improved air and water movement.

Sandy soils that are low in humus should be amended with fine-textured organic matter. Well-rotted manures, compost, leaf mold, or well rotted fine bark dust are all excellent.

It is well known that lilies thrive better in reasonably fertile soil than in an impoverished substrate. The best plan is to improve the soil well before planting time by digging it thoroughly and loosening the subsoil, if necessary. Incorporating well-decayed organic matter before planting is highly recommended. Cow or horse manure is a good amendment, but it must be well aged. The finest lilies were growing in soil amended with liberal quantities of horse or cow manure; however, care must be exercised in the use of manures, which can cause both nutritional and disease problems-in particular, they encourage high acidity, a condition ideal for the growth of the fungus Fusarium. This problem can be avoided if the manure is used as a mulch rather than mixed with the soil.

Planting time

Most lilies do best when they are planted in early fall. The lily bulb naturally forms basal or contractile roots following fall planting; these anchor the bulb. Warm soil temperatures are critical for the development of these first roots, so late planting in cold soil does not produce the desired root growth.

A notable exception is Lilium candidum (Madonna lily), which must be replanted in late July or August, a few weeks after it flowers. At this time the bulbs are fully formed and dormant. After replanting, or if left in place, they naturally produce leaves in late summer or early fall and overwinter in this stage. This characteristic dictates shallow planting so that the leaves can reach the surface quickly and begin to photosynthesize; the bulbs of the Madonna lily should not be covered with more than 2.5 to 5 centimeters (1 to 2 inches) of soil. This is a Mediterranean plant adapted to dry summers and wet, mild winters, and its winter growth pattern is typical of many warm-climate bulbous plants.

Lily bulbs can also be planted in the spring when soil conditions permit it. Commercial growers store bulbs at temperatures just above freezing after the turn of the year. This conditions the bulbs to sprout quickly after they are removed from cold storage and exposed to warmer temperatures. It is therefore imperative that bulbs purchased in spring be kept as cool as possible before planting; if soil conditions are unfavorable, they can be stored in the vegetable bin of a household refrigerator until planting is possible. It is strongly advisable to postpone planting until the soil is warm and not waterlogged. An early spell of fine spring weather can be tempting, but it may be followed by a miserable cold period-hardly ideal conditions for bulbs conditioned to sprout and grow rapidly.

Planting depth

The factors that determine how deep to plant a lily bulb include the habit of growth of the particular species or hybrid, the size of the bulb, the type of soil in which the bulbs are being planted, and the local climate. Most lilies produce roots from the stem directly above the bulb, along with the roots that emerge from the base of the bulb. The stem roots die annually with the stem at the end of the growing season. These roots are very important in feeding the plant during its active growth; therefore, the bulbs should be planted deep enough to allow ample development of the stem roots.

A good rule is to cover the bulbs with soil to a depth equal to three or four times their length (base to tip). Stem-rooting lilies with large bulbs, such as trumpet hybrids, may be covered with as much as 25 centimeters (10 inches) of soil.

Another reason for deep planting is that it keeps the bulbs cool during the heat of summer. The bulbs must be protected from the temperature fluctuations that occur in the top few inches of the soil (high soil temperature is conducive to the development of disease). Many lily enthusiasts plant bulbs too shallowly for optimal results.

The Madonna lily is an exception about planting depth as well as planting time. It produces roots only from the base of the bulb, not from the stem. Shallow planting is thus appropriate for it.

Some modification in planting depth may also be dictated by soil type and climate. Bulbs in heavy soil must be planted less deeply than those in lighter, warmer, sandy soils. In very warm regions, the bulbs benefit from deeper planting, which protects them from high temperatures in the soil near the surface.

Small seedling bulblets, or yearlings, should be covered with about 5 centimeters (2 inches) of soil, depending on their size. Their basal or contractile roots pull the young bulbs to a deeper level as they increase in size. This occurs with larger bulbs as well; if the soil structure permits it, they eventually draw the bulbs down to their preferred depth.

The gardener should be aware in placing lilies that in some groups, such as Orientals and hybrids of Lilium wilsonii and L.lankongense, the stem often does not rise straight up from the bulb but extends horizontally for a few inches before emerging. This is a strategy to allow the stem roots enough soil to develop adequately. The deeper a bulb is planted, the less likely this is to happen. This special attention must be given to the species and hybrids showing this stoloniferous habit.

Planting techniques

There are several techniques that can be used in planting lily bulbs. Some require little physical effort, and others are more strenuous. The best method is to dig a single hole large enough to accommodate all the bulbs that are to be planted in a group; the depth depends on the size of the bulbs and the other considerations just mentioned. For example, to plant bulbs of the Asiatic clone 'Connecticut King' that average 5 centimeters (2 inches) long, dig a hole 20 centimeters (8 inches) deep. Loosen the subsoil at the bottom of the hole to improve the drainage. Set the bulbs on their bases with enough space between them to allow full development during growth. A minimum spacing of 15 centimeters (6 inches) is best for Asiatic clones, with as much as 45 centimeters (18 inches) for taller lilies such as trumpets and Orientals. The ultimate height and habit of the plants also affects the spacing chosen; for example, a variety that produces a broad, branching inflorescence will need more room to display its flowers than one with a tall, narrow habit. Overcrowding must be avoided, not only for aesthetic reasons but also because it restricts air circulation and thus promotes disease.

Climate

As a general rule, lilies enjoy cold winters and warm summers but dislike heavy humid weather. Lily growers in the Southern United States and Japan have continuing problems with fungus disease because of hot humid summers. Where winter temperatures rarely go below 40°F (4.4°C), lily bulbs should be lifted in October and refrigerated for between four to six weeks to imitate a cold winter period.

Of course, climate also affects flowering times and given a warm, wet spring lilies will flower earlier than after a cold dry spring.

Plants growing in shade will frequently produce fewer blooms than those growing in sunny positions. Candidums planted in shade, for example, tend to flower 10-14 days later than those planted in full sun.

Preparing the soil

Lilies like the classic conditions of a free-draining, moisture retentive soil. In spite of appearance, these two conditions do not cancel each other out. Free-draining means that any excessive water can easily drain away, leaving sufficient moisture, usually held in humus, to supply the plant.

Wet, stagnant conditions will cause the bulbs to rot. If the soil is inclined to be wet, some form of drainage system should be installed. Alternatively a deep raised bed could be built, containing a better soil, so that the bulbs are lifted above the surrounding area. Heavy soil should be lightened with the addition of grit and humus, the latter in the form of manure or compost, both of which should be well-rotted.

A dry soil should have organic material added to it. This not only provides the plants with moisture held in its fibrous texture, but also supplies nutrients which are likely to have been leached away in the rapidly drained soil.

The soil should have a good depth to it and should be prepared to at least 20 in (50 cm). Double digging with humus, and grit if necessary, added to the lower as well as the upper spit is the best way of achieving this. Prepare a decent-sized area and ensure that any water that collects in the bottom of the bed can drain away, as small areas thus prepared can act as sumps and partially fill with water with dire consequences to the lilies.

If well-rotted manure or compost has been added to the soil as it is dug then no further fertilizers need adding at the time of preparation. If manure or compost has not been added, then a general fertilizer with a balanced formula can be added and well raked in. Later the ground can be top-dressed with a potash-rich fertilizer.

The acidity of the soil should be about neutral, pH 6.0, 6.5, 7. This can be tested with a simple kit for pH testing available at garden centers and nurseries. For some lilies it will be necessary to adjust the soil pH with lime to raise the alkalinity. Other soils may possibly need humus added, which tends to make soil more acid, but pH 7 will suit most lilies and there should be little need to alter it.

A very important point to note is that when the soil is prepared all perennial weeds should be eliminated, through hard weeding or perhaps with the aid of chemical herbicides. Once the lilies are in place it is essential that they are not disturbed as they are brittle. Any attempts to remove perennial weeds at this stage could cause damage that will not be repaired until the next season. Annual weeds are not so important as most of them are surface rooting, but they still use up moisture and nutrients as well as harboring disease.

Sun and shade

Lilies enjoy getting their heads in the sunshine, where insects are attracted by their color and scent. However, quite a number - probably the majority - will be happy growing in light woodland, or the equivalent in modern gardens, under trees and shrubs where the bulbs will grow and enjoy dappled sunlight. In such sites trees and shrubs not only provide a backcloth for the splendid lily flowers, but roots working below will usually ensure that drainage is good by encouraging healthy soil structure and channeling surplus water upwards, to be lost through transpiration from the leaves.

Enough is, of course, a sufficiency. Lilies do not relish finding themselves below such impenetrable masses as provided by most conifers, although at some little distance they could benefit from the acidity promoted by fallen needles.

Air

Stagnant air, especially in humid summer climates, favors the development of the most prevalent lily disease, Botrytis blight; wet foliage also contributes to it. Constant air movement, however, speeds evaporation and drying of the foliage. This tells us to choose a site for lilies where we often feel a slight breeze-a slope or an area open at both ends to the prevailing winds.

Any hollow or pocket where air circulation is poor is also likely to act as a frost trap in spring. Frost damage may result in the loss of a season's flowering and in damage to the emerging foliage.

Lilies growing in their natural habitats are usually protected from high winds by the shelter of grasses, shrubs, and nearby trees. This should also be kept in mind when choosing a site. Lilies need not be planted in borders as flowering annuals and perennials often are; a clump of lilies can stand on its own as a landscape feature. The necessary wind protection can be provided by small trees, shrubs, or even a fence.

Moisture

In winter, many wild lilies are covered with snow and so are kept free from excessive wet. Spring rain and melting snow provide an abundance of moisture as roots move into top gear. In the garden, we need to minimize the effect of surplus winter water, and then maximize on spring and summer rains. Good soil structure and mulches help make the most of such rain. Water butts can be used to collect rainwater. Grown between shrubs, groups of lilies need not be in severe competition for water and will very rarely need watering as a matter of life or death. When watering, keep foliage, stems and flowers dry.

Light

Most lilies thrive best in sunny conditions. Where light is restricted, they have a strong tendency to lean toward the light. This is especially true of Chinese trumpet lilies and their hybrids, which must have abundant sunlight for good performance and maximum beauty.

There are a few kinds of lilies, such as Lilium martagon, L. hansonii, and their hybrids, that enjoy light shade. The later-flowering Oriental lilies also benefit from shade during the hottest part of the day, because their flowers tend to bleach out in strong sun. In choosing exposure, much depends on the local climate: in hot regions, most lilies do best with some afternoon shade. Nonetheless, very few lilies can survive where the shade is dense, such as on the north side of a house or under large conifers.

Heat and cold

Lilies are remarkably resilient against both cold and heat. The bulbs are safely inured to the winter's cold, but occasionally can be severely damaged by a heavy late frost when they have fresh young growth well above the ground. However, it has to be a very sharp, prolonged frost to cause a lot of damage. Grown between other plants, the bulbs are partially protected, but warnings of such severe frosts make it worthwhile giving extra protection to especially valued plants with a covering of straw, leaf or bark litter, or even sheets of newspaper or plastic sacks. Almost any thing will serve for the few hours needed to conserve heat and turn the frost aside.

Sun and heat rarely cause problems in temperate parts of the world. Trouble can be encountered if the rate of water transpiration from foliage is accelerated at a time when the ground has become almost desert-dry and the reservoir of soil water is very severely depleted. A thorough soaking of the ground will be required.

Fertilizers

The kind and amount of fertilizer needed depends on the fertility of the soil. No fertilizer may be necessary where a variety of other plants are growing well already.

Most kinds of lilies prefer a slightly acid soil, with a pH of 6.0 to 6.5 being best. A complete, well-balanced fertilizer containing nitrogen, phosphorus, and potassium (typically-in a ratio of 15-15-15) should be applied when necessary to ensure good growth. An application of garden lime maybe necessary if the soil is very acid.

In areas where the soil is very alkaline, lilies may be grown in raised beds made up of acidic compost, or in containers. There are also products on the market to acidify lime soils, but they are not as satisfactory as the former method. A few species of lilies are native to limestone areas and should tolerate alkaline soils well.

The point to emphasize about fertilizing lilies is that excessive application can be harmful because it promotes soft growth and makes the plants more susceptible to disease. This is true where the soil is heavy or rich in humus; such soils tend to be naturally high in nutrients, and artificial fertilizing should be done judiciously if at all.

Artificial fertilizer is best applied when the lily shoots are at the spear stage, just before the leaves unfurl. A handful of well-balanced granular fertilizer (12-12-12) should be gently worked into the soil around each plant. Especially suitable is a six-month slow-release product such as Osmocote, in a 20-20-20 formula. One application of this should keep the lilies happy for the entire season.

An old practice sometimes used to maintain lilies' health and vigor was to scrape away a couple of centimeters (an inch) of soil just as the lilies emerged and replace it with a mulch of well-decayed cow or horse manure. Well-decayed composts are also recommended.

Replanting lilies

It is sometimes a problem to determine how long a clump of lilies should be retained in place before the plants are moved to a fresh location. When the bulbs have offset to produce several stems, it is usually desirable to separate the clump in fall and replant the bulbs.

Asiatic varieties tend to require lifting and replanting on a regular basis. Most of them form many bulblets along the underground parts of the stems; as a result, the clump becomes very crowded and flowering declines. Lifting and division should be done about every third year with stronger Asiatic varieties.

Sometimes it is obvious that a group of lilies is not thriving as it once did. In such cases, a move to a new location and fresh soil usually restores the plants to their former vigor. This replanting is best done three or four weeks after flowering. At this time, check the bulbs for disease, especially basal rot (Fusarium). Discard severely infected bulbs and treat the others with a suitable fungicide before replanting

Pruning

Undeveloped seedpods should be removed after flowering if seed is not desired. This allows the bulbs to store as much food as possible. In the fall, after frost has been severe enough to end all leaf formation and after the tops senesce, the stems should be cut to the ground, removed, and if possible burned. This helps to remove disease organisms from the garden. Be sure to mark the site of the bulbs with a stake so they will not be damaged if work if done in the dormant bed.

Weed control

Lily hobbyists must be cautious in the use of herbicides to control weeds. These chemicals can act differently in response to climate and soil conditions. The one product highly recommended to control weeds before the lilies emerge is Round-up (main ingredient glyphosate). This excellent herbicide is effective against perennial weeds such as Canadian thistle, dock, bindweed, and crabgrass, killing them entirely if application is timed right. Round-up must be applied in spring for best results; this is best done when the weeds have enough foliage to absorb the chemical, but before nearby ornamentals (including lilies) emerge.

Irrigation

Lilies require adequate moisture during the growing season, before flowering, and for a few weeks after it. The moisture level can then be decreased gradually. The frequency of watering depends both on the local weather and on the moisture-retaining quality of the soil. The lily bed should never be saturated or waterlogged, nor should it dry out completely.

Soaker or "leaky" hoses are an excellent means of watering when groups of lilies are planted together. They can simply be laid on the ground around the planting, remaining as long as irrigation is required. Drip irrigation has become a sophisticated field, and a visit to a specialty garden store offers many ideas. Overhead watering may damage lilies, either physically when the sprinkler stream strikes the stems, or through promoting Botrytis and other fungal diseases; nevertheless, it is used in commercial plantings, which are in open, sunny fields where disease is carefully monitored.

Early blooming varieties, such as Asiatics, and late-blooming lilies, such as the August-flowering Orientals, have quite different moisture requirements. When the early flowering varieties should be on the dry side, the late ones are just approaching their flowering period and peak moisture requirement. Thus, it is best not to plant early and late bloomers in proximity.

In areas that are wet in summer, such as the mid-Atlantic region of North America, good drainage and cool soil are the keys to growing lilies. Recall that although many important species of lilies come from hot, humid Japan and eastern Asia, lilies tend to grow on steep slopes in volcanic soils. Atmospheric humidity is another problem, because it promotes Botrytis and other fungal diseases; good air circulation mitigates this problem.