A question to resolve before buying bulbs is whether they will be encouraged to spread, and if so how far. With the exceptions of the hyacinth and ornamental onions, spring-flowering bulbs tend to multiply, eager to conquer the earth, especially when they are happy where they are. Daffodils, snowdrops, and lily of the valley are among the many bulbs that surprise us in the spring by sending up twice as many shoots as in the previous year. Do not plant just one bulb or just one variety. Bulbous plants look their best in clusters, preferably in a free form giving the impression of a natural drift rather than in a single file suggesting regimentation.
Prudence calls for picking at least two species advertised as blooming in each month.
No matter how impulsive or deliberate your bulb selection is, fine, porous soil rich in organic content is indispensable. Bulbs will not thrive in hard-packed clay or a thin layer of soil on top of urban rubble. Before planting, you must dig up the area 12 to 18 inches deep and add liberal amounts of dried manure, peat moss, compost, or leaf mold. The first gardeners who had the bold idea of digging up bulbs and planting them around their houses must have learned quickly that it is not good to protect them from cold weather. Strange as it seems, bulbs must have the harsh winds and the killing freezes of winter.