The name "lily" is given to several different flowers, but there is only one true lily family. That genus is called "Lilium," and it is distinguished by large, open flowers situated atop tall, sturdy stems. Within the genus are several different groups. The three most common are Asiatic lilies, Oriental lilies and Trumpet lilies.
Asiatic lilies are prized for their bright colors, including shades of pink, red, orange and yellow. Some are also white or bi-colored. Asiatic lilies have strong, straight stems with multiple blooms and most cultivars are not fragrant. They grow best in full sunlight and moist, rich soil. Asiatic lilies are hardy in U.S. Department of Agriculture plant hardiness zones 5 through 9 and bloom in early summer. Lilies in this group include Lilium amabile, which has red flowers and spreads quickly, Lilium bakerianum, which can grow at altitudes of over 11,000 feet above sea level, Lilium callosum, which have 3-foot tall stems lined with as many as 12 flowers, and Lilium cernuum, which unlike most Asiatic varieties, does have a light scent.
Oriental lilies have a much stronger fragrance than their Asiatic counterparts. Also desirable for their elaborately frilled flower petals, these lilies are hardy in USDA zones 7 through 9. Oriental lilies bloom in mid and late summer and grow best in full sunlight and moist, organic soil. Lilies in this group include Lilium auratum, which has white petals streaked with gold bands, Lilium japonicum, which thrives in cool soils and is a good companion to rhododendrons, Lilium rubellum, which has delicate pink flowers and grows at altitudes of 9,000 feet, and Lilium speciosum, which has a very strong, sweet scent.
Trumpet lilies have a distinctive, elongated shape that gives rise to their common name. Most cultivars are white, yellow or bi-colored. Lilium longiflorum, or the Easter lily, is one of the most common. It grows in USDA zones 4 through 8 and features large, creamy white flowers. Other Trumpet lilies that grow in the same zones include Lilium regale, which are pink on the outside, white on the inside and have bright yellow throats, and Lilium leucanthum, which have greatly curved petals and prominent stamens.
Lilium candidum, or the Madonna lily, is hardy in USDA zones 7 through 9. This lily, which can reach heights of over 3 feet, has pure white, star-shaped flowers that bloom in the summer. Lilium superbum has very distinctive flowers with bright orange, freckled petals that curve sharply backward. Commonly called the Turk's cap lily, it is hardy in USDA zones 5 through 8.
- Iowa State University Extension: Lilies in the Landscape
- North Carolina State University Extension: Lilium - Asiatic hybrids
- North Carolina State University Extension: Lilium Candidum
- North Carolina State University Extension: Lilium - Oriental hybrids
- Missouri Botanical Garden: Lilium Longiflorum
- Pacific Bulb Society: Lilium Asiatic Section
- Pacific Bulb Society: Lilium Oriental Section
- Pacific Bulb Society: Lilium Trumpet Selection
- Missouri Botanical Garden: Lilium Regale
- North Carolina University Extension: Lilium Candidum
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