The structure of the lily bulb
The lily bulb, made up of a number of succulent, fleshy scales, does not have an outer protecting layer like the tulip,and crocus, and is therefore unable to tolerate prolonged dry storage. One of the main essentials for satisfactory growth is good, healthy bulbs with undamaged, live and fleshy, sappy scales. Bulbs which are displayed without nrotection in the dry and warm atmosphere of shops, including bulbs which have been stored for too long in polythene bags, are apt to be dried-up and wrinkled, with only a few brown, wizened, lifeless . If such bulbs are bought and planted, their chance of success is minimal and their lifespan, because their damaged roots impair their ability to take up nourishment, is reduced.
Bulbs should be out of the soil for as short a time as possible, and ought to be obtained from the nearest possible source to reduce the risks involved during long journeys. For most European growers, as most bulbs are imported from cither Holland or the United States, the only practical safeguard is early ordering in the hope that delivery is received from the first consignment, usually during late October or early November. Bulbs usually arrive packed in damp peat inside a polythene bag, and should be stored in a cool place if immediate planting is impossible.
As soon as soil preparations are completed, preferably during early autumn, the site should be covered cither with, straw or straw mats, to protect it from frost and heavy rain; in this way bulbs, even if they arrive later than anticipated, can still be planted.
If American wild lilies are planted after September, they are unable to develop roots and decay inevitably follows.
The native habitat of lilies provides the goodthey like and which they naturally must also have in cultivation; waterlogged soils mean certain death to them. In their natural surroundings they are found growing on slopes, some exceptionally steep, but always on porous types of soils, whether in rock-beds covered with -mould, between boulders in soil pockets rich in humus, or on gravelly, sandy soils with humus cover.
In Japan, L. anratiini and L. speciosnm grow on exceptionally free-draining volcanic rubble and ash. The photographs of lilies in their wild surroundings published in the American and English Lily Year books and also in E. H.Wilson’s Lilies of Eastern Asia illustrate these points, and always show L. regale, L. henryi, L. ivallichianuni, or L. philippinense growing on steep and often rocky ground. The only exceptions to the rule are the bog-type lilies growing on the Pacific coast of America, which withstand periodic flooding. As lilies are certain to fail in waterlogged loam and clay soils, such soils must either be avoided or be well drained before the planting stage is reached.
Selection of planting site
Sloping sites with naturalare best, and have the additional advantage of being easily terraced through building up the lower levels with soil dug from the higher parts. Stone walls, or strategically placed, medium-sized rocks effectively retain the soil banks, which should have a barrowload or two of coarse gravel, or builders’ rubble, placed at their lowest point to assist drainage.
If planting must be on level ground, it is usually a good plan to raise the level of the bed with additional soil and surround it with stones, bricks or planks.
To satisfy the drainage requirements of the difficult wild Japanese and North American lilies, which must have a soil depth of 20 inches, the planting hole or trench should first be lined with brushwood, topped with stone rubble, and filled with soil previously enriched with additions of sand, peat and-mould.
Soil conditions are even more important than planting positions. Light, sandy soils need additional nutrients and an improved texture most satisfactorily provided by the incorporation of, leaf-mould, or peat (peat is better able to combat difficulties of fertilizer or pH content than soil alone).
Sandy loams rich in humus provide the ideal ground for lilies, but even they are improved, and certainly made more friable, if quantities of peat can be forked in.
Mixing sand and peat with heavy soils lightens them and improves their permeability, while well-rotted turves and leaf-mould provide nutrients for the bulbs.
Heavy soils and clay soils must receive applications of sand, peat and . leaf-mould, and should preferably be turned several times before being planted. The heaviest soils also benefit from applications of StyromulT -flakes of expanded polystyrene. Although these flakes have no manurial value, they help to improve the texture of the soil, solely by their physical properties; they retain water only on their outer surface, and do not become saturated. They lead to permanent loosening of the soil. The flakes of Styromull are scattered over the soil surface from just above ground level, preferably on a wind-free day, and worked into the ground with a spade or a rotary cultivator.
The effectiveness of Styromull applications in improving the texture of soil was demonstrated in 1963 at the International Horticultural Show in Hamburg, where bulbs of irises and lilies were planted in heavy soil with the addition of 20-30 per cent Styromull.