The primary bulb species used for gardens and landscapes include: true bulbs, corms, tubers, tuberous roots, rhizomes, and enlarged hypocotyls. All are "Geophytes" and, collectively, they are commonly called "Flower Bulbs". Although each specialized storage organ is morphologically different, their basic function is to serve as an organ for survival of the species. (See De Hertogh and Le Nard, 1993). In this bulletin, we refer to specific underground storage organs as corms, tubers, etc. only when citing the genus or species.
Fall planted bulbs that flower either in the spring or very early summer greatly enhance home gardens, parks, office buildings, apartments, townhomes, condominiums, and other landscaped facilities. They offer a tremendous range of flower colors, shapes, sizes, and plant heights. By selecting bulbs (Table 2) from the very early flowering period to the very late flowering period, four continuous months of flowering can be obtained. However, they have a wide range of temperature hardiness. Thus, all flower bulbs are not suitable for all 11 climatic zones that exist in the U.S. and Canada . To assist gardeners and landscapers, the basic cultural requirements and characteristics for spring flowering bulbs are summarized in - Table 1 and Table 2.