A flower bulb is really an underground storehouse and flower factory. Within the bulb is just about everything the plant will need to sprout and flower at the appropriate time. Split a bulb in half and you will see this clearly.

In the basal center portion of the bulb are the leaves cradling a baby bud. (In many species, this bud already has the appearance of a flower while still in the bulb!) Surrounding the bud is a white, meaty substance called the scales. In true bulbs, it is these scales which contain all the food the bulb will need to flower and thrive. Anchoring the scales and the floral stalk which holds the bud is the basal plate. This plate at the bottom of the bulb also holds the roots of the plant. The entire package is protected by a thin outer skin called the tunic.

All this remarkable organism needs from humans is to be placed in the ground at the appropriate season of the year, given a liberal drink of water and then left alone. The bulb does the rest!

Technically speaking, many popular "bulb" flowers are not produced from true bulbs at all. Crocuses and gladioli, for example, are really corms, while such favorites as dahlias and begonias are really tubers.

The differences between bulbs and corms are slight, and indeed the two look very similar. The main distinguishing trait is the method of storing food. In corms, most of the food is stored in an enlarged basal plate rather than the meaty scales, which in corms are much smaller. Corms generally tend to be flatter in shape than round, true bulbs.

Tubers and roots are easily distinguished from bulbs and corms. They have no protective tunic and are really just enlarged stem tissue. They come in a variety of shapes, from cylindrical, to flat, to just about any combination you can imagine. Many come in clusters.

Generally, however, you are safe using the term "bulb." Bulb has commonly come to mean any plant which has an underground food storage capacity.

Bulbs fall generally into two groups: spring-flowering (which are planted in the fall) and summer-flowering (which are planted in the spring). A more accurate grouping, however, divides bulbs into hardy and tender varieties.

As a rule, spring-flowering bulbs are hardy bulbs. These bulbs are planted in the fall, generally before the first frost, and can survive (and indeed require for sprouting) the cold winter months. Many hardy bulbs, such as daffodils, perennialize well and can be left in the ground to flower year after year.

Most summer-flowering bulbs are tender bulbs. These bulbs cannot survive harsh winter conditions and must be planted in spring after the last frost of the season. To enjoy these bulbs year after year, they must be dug up in fall and stored indoors over the winter. A notable exception is the lily. Many summer-flowering lily varieties are quite hardy and can be planted in either fall or spring.

Bulb flowers are among the most popular and best loved in the world. Spring-flowering bulbs such as tulips, crocuses, hyacinths, daffodils, and irises are universal symbols of spring. Their lush and colorful flowers are the first to bring life back to a barren winter landscape. Summer-flowering bulbs such as dahlias, begonias and anemones bring variety, texture, unique color and long flowering times to summer gardens. Planted with care and planning, bulbs can keep a garden alive with color from the last snows of winter through the first frosts of fall.