Grow in organically rich, fertile, medium moisture, well-drained soils in full sun. Best with cool, moist winters and warm dry summers. Plant bulbs 4-6” deep (three times the depth of the bulb) in fall. In heavy clay soils, a slightly shallower depth is best. Space bulbs 2-5” apart depending on plant size. Tulips may be grown as perennials or as annuals. Species tulips often perform better than hybrid plants as perennials. When growing tulips as perennials, promptly remove spent flower stems after bloom (prevents seeding), but do not remove foliage until it yellows. In most cases, tulip performance declines substantially starting with the second year. Many growers prefer growing tulips, particularly hybrids, as annuals.
Tulips are popular spring flowers that come in nearly all colors except true blue. Shape is often a cup with a teardrop form. Bowl, goblet and star shapes also exist. Some flowers are double. Each flower has six petal-like tepals. Tepals may be fringed or ruffled. Basal leaves are blue/gray-green in color with a broad oval shape, but some varieties have strap-shaped or long narrow leaves. Tulips are generally organized into 15 divisions based upon flower shape and origin. Bloom time varies.
Single Early Group (Division 1). Single, cup-shaped, early to mid-spring tulips on stems to 10-14” tall.
Double Early Group (Division 2). Double, peonylike, mid-spring tulips on stems to 12-16” tall.
Triumph Group (Division 3). Single, cup-shaped, mid to late-spring tulips on stems to 16-24” tall. Crosses between single early, Darwin and cottage types.
Darwin Hybrid Group (Division 4). Large mid to late spring tulips on stems to 20-28” tall. Some have contrasting eyes or penciling.
Single Late Group (Division 5). Single, cup/goblet-shaped, late spring (May) tulips on stems to 18-30” tall. Includes Darwin and cottage tulips. Some cultivars have more than one bloom per stem.
Lily-flowered Group (Division 6). Single, lilylike, goblet-shaped, mid to late spring tulips with pointed reflexed tepals on stems to 18-26” tall.
Fringed Group (Division 7). Single, cup-shaped, mid to late spring tulips with fringed tepals on stems to 14-26” tall. Fringe may be in a different color.
Viridiflora Group (Division 8). Single, cup/rounded/bowl shaped, late spring flowers (May flowers) streaked with green on stems to 15-20” tall.
Rembrandt Group (Division 9). Single cup-shaped tulips striped with various colors. True Rembrandt Tulips are no longer sold in commerce because the striping is caused by a virus.