The term "lily" is often applied to a wide variety of plants, but true lilies belong to the genus Lilium, comprising over 100 species and numerous cultivated hybrids. These are herbaceous perennials growing from bulbs, which are composed of fleshy, overlapping scales without a protective outer tunic. True lilies are characterized by their large, often fragrant, flowers with six tepals (petals and sepals that look identical) and prominent stamens with large anthers. The main horticultural divisions, such as Asiatic and Oriental, are primarily based on their geographical origin, botanical characteristics, and subsequent breeding.
Asiatic lilies are among the earliest to bloom and are derived from species native to East Asia. They are celebrated for their hardiness and adaptability. Plant specimens are typically of moderate height, ranging from 2 to 4 feet, with sturdy, upright stems. Their leaves are narrow and lance-shaped, arranged in whorls or spirals along the stem. The flowers are generally upward-facing, outward-facing, or pendant, and come in the widest array of vibrant colors except true blue. A key botanical distinction is their lack of a strong fragrance. Their petals are often smooth and may feature dramatic spotting or brushmarks. They propagate readily and are well-suited to colder climates, thriving in well-drained soil and full sun to partial shade.
Oriental hybrids are primarily derived from Japanese species like Lilium speciosum and Lilium auratum. They bloom later in the season, following the Asiatics. These plants are often taller and more imposing, frequently reaching 4 to 6 feet in height. Their foliage is broader and more scattered along the stem compared to Asiatics. The flowers are renowned for their intense, sweet fragrance and enormous size. They are often outward-facing or pendant, with strikingly textured petals that can be ruffled, recurved, or edged in a contrasting color. Many feature prominent papillae (small fleshy projections) and deep crimson or pink spotting. They prefer acidic, well-drained soil and are slightly less hardy than Asiatic varieties, often benefiting from winter mulch in cooler zones.
Beyond the two most common groups, several other types are significant. Trumpet and Aurelian hybrids, derived from species like Lilium regale, feature long, trumpet-shaped flowers on very tall stems and possess a powerful fragrance. Longiflorum hybrids, including the classic Easter Lily, are known for their pure white, trumpet-shaped flowers and year-round forcing capability for the potted plant trade. Species lilies, such as the vigorous North American Turk's Cap lily (Lilium superbum), represent the wild forms from which hybrids are derived; they often have smaller, recurved petals and are highly valued by native plant enthusiasts for their ecological value and natural elegance.
Despite their differences, most lilies share core botanical needs. They are photoperiodic, requiring specific light conditions to initiate flowering. All require excellent drainage to prevent bulb rot, as their unscaled bulbs are prone to fungal diseases. Planting depth is critical; a general rule is to plant the bulb at a depth three times its height to ensure stable root and stem development. After flowering, it is vital to allow the foliage to photosynthesize and die back naturally to replenish the bulb's energy reserves for the next growing season, as they are true perennials.
