Tulip Fields, Keukenhof, The Netherlands

Growing salable tulips from offsets requires a year or more of growth before plants are large enough to flower. Tulips grown from seeds often need five to eight years of growth before plants are flowering size. Commercial growers usually harvest the tulip bulbs in late summer and grade them into sizes; bulbs large enough to flower are sorted and sold, while smaller bulbs are sorted into sizes and replanted. Holland is the main producer of commercially sold plants, producing as many as 3 billion bulbs annually.
Introduction to Western Europe
Although it is unknown who first brought the tulip to Northwestern Europe, the most widely accepted story is that it was Oghier Ghislain de Busbecq, an ambassador for Ferdinand I of Germany to Suleyman the Magnificent of the Ottoman Empire. He remarked in a letter that he saw "an abundance of flowers everywhere; Narcissus, hyacinths and those in Turkish called Lale, much to our astonishment because it was almost midwinter, a season unfriendly to flowers." However, in 1559, an account by Conrad Gessner described tulips flowering in Augsburg, Bavaria in the garden of Councillor Herwart. Due to the nature of the tulip's growing cycle, tulip bulbs are generally removed from the ground in June and must be replanted by September to endure the winter. While possible, it is doubtful that Busbecq could successfully have had the tulip bulbs harvested, shipped to Germany, and replanted between his first sighting of them in March 1558 and Gessner's description the following year. As a result, Busbecq's account of the supposed first sighting of tulips by a European is possibly spurious.