Varieties and production of tulip plant.
There are now thousands of varieties and their classification has become quite complex. Among the types most commonly seen are: cottage tulips, which bloom in May and have a wide range of solid colors; parrot tulips, having, having twisted and slashed petals; early flowering tulips, used mainly for winter forcing in greenhouses; Darwin tulips, a later flowering group noted for their long stems and large flowers; breeder tulips, characterized by flowers in bronze and purplish tints.
Tulips are erect plants with thick, crisp, basal and stem leaves, and saucer or bell-shaped, usually erect and solitary flowers. Their low cost, easy culture, form and variety of color, long blooming period have made them the most popular spring-flowering bulb for many centuries.
Tulip via Wikipedia
Tulips should be planted in late autumn, the bulbs being placed 6 to 8 in. or more below ground, and mulched during the period when the ground is frozen. Tulips grow under very adverse conditions; they prefer a rich, sandy loam in full sun.
During World War II, when no imports could be obtained from Holland, bulb growers began to raise tulips in the north-western United States. In the first half of the 17th century, tulips became so popular, and speculation on the Dutch crop was so great, that fantastic sums were paid for single bulbs.
Production of tulip bulbs has long been a major Dutch industry, and bulbs from Holland are exported in great quantities. In recent years, there has been a growing interest in the wild species of tulip, many of which are adapted to the rock garden because of their small size.