Bulbs should be planted in a well-drained, deep, rich soil in order to develop successfully. In wet soils put a handful of sand under each bulb to keep the water away from the immediate vicinity of the bulbs. In wet locations the beds should be raised. Hyacinths require a sandy soil and soon become diseased in heavy soils. Few lilies will succeed in limestone soil. Lilies require extra good drainage and rich soil. Some will do well in heavy soil, as the madonna lily and the tiger lily. It is best to surround lily bulbs with sand, and where drainage is not ideal, plant the bulbs on one side so that water may not collect in the heart of the bulb.
No fresh manure should ever touch a bulb, but well-rotted manure may be incorporated deep in the soil before planting with the best of results. The manure should be accessible to the feeding roots but be kept away from the bulb. Do not use manure at all unless the bed is excavated to a depth that makes it possible to spade the manure in below the level on which the bulbs are to rest. Tulips are less apt to be injured by manure than are narcissi. For planting with a trowel or dibble, bone meal only should be used. Leaf mold and sand should be added to heavy soils. Bone meal used with bulbs tends to increase the size of the blooms. Liquid manure, added liberally when the plants are budding, has often given excellent results. To increase the development of new bulblets and especially of gladioli, a fertilizer containing a large percentage of potash is desirable.
Unless a bed of bulbs is planted at uniform depth they will not bloom uniformly. It is a good practice to excavate a bed to a given depth, place the bulbs as desired over the bottom, and then cover all to the same depth, thus making certain that they are evenly planted. The larger and stronger bulbs are, the deeper they may be planted. They may be planted deeper in sandy soil than in heavy clay soil. A general rule for planting depth is three times the average diameter of the bulb. Bulbs are frequently planted too shallow. For depths at which to plant bulbs, also distances apart, see "Bulb Table" (Plate IX, Page 46). When planted in holes made with a dibble, put loose dirt or sand in the bottom of the hole to avoid air space. Planting with trowel or dibble, however, should not be done where uniform show beds are desired. For lawns, bulbs may be dibbled in, but it is better to cut the sod and press back after planting. This is done in the fall when lawns are soft from rains.
Bulbs lie dormant, to all appearances, over winter, and should be' thoroughly mulched to insure that they do not start to grow in any unseasonable warm spell of weather, and also in order to prevent heaving. Mulch with straw or leaves to a depth of four inches to six inches, but do not add this mulch too early; wait till a fairly thick crust has been frozen over the ground. Lilies always require heavy protection and will succeed better in partial shade. Remove the mulch or litter in spring before warm weather and after damage from freezing is past. The coarse part of the mulch should be picked off carefully, care being taken not to injure the tops of the bulbs. The finer pieces of mulch may be worked into the soil, if the cultivating is done cautiously.
Many bulbs, like the varieties of crocus and certain varieties of narcissi, will continue to multiply by developing small bulblets and in that way produce a flower effect for a considerable number of years. Other bulbs, like certain varieties of the tulips and other varieties of narcissi, will have their energy sapped during the first one or two years. They will not reproduce bulblets and the result is that in order to continue the flower effect new bulbs must be purchased and planted in their place at the.end of two or three years. Spanish iris and also the English iris will, under ideal conditions of soil and cultivation, continue to develop new bulbs and to multiply. For this reason they can be left in the ground during a number of years. In cutting flowers from bulbs it is quite necessary that some leaf surface should remain after the flower stalk has been removed. This leaf surface provides a "stomach" for the plant, in which digestive functions continue and new food is supplied to the bulb for the purpose of enlarging it and for the purpose of forming new bulblets. The gladiolus is the best example of bulbs which are reproduced in the average garden by new bulblets. Many varieties of gladioli, however, will not reproduce bulblets if the flowers are removed. None of the varieties of the gladiolus will produce new bulblets or make strong bulbs if, when the flowers are cut, all of the leaves are removed.