The term “lily” is often used loosely in conversation to describe many different lily-like flowers. Botanically, the name is reserved exclusively for plants belonging to the genus Lilium. Many popular purple flowers that share the iconic shape or height of a lily are actually members of entirely different plant families, meaning the flower a person seeks is frequently not a true Lilium.
Identifying True Purple Lilium
True purple Lilium exist, though pure violet shades are uncommon. Most successful cultivars present as deep shades of maroon, burgundy, or nearly black purple. Cultivars like ‘Purple Prince’ and ‘Purple Lady’ are Oriental-Trumpet hybrids showcasing a striking deep grape color on massive, upward-facing blooms. The Asiatic lily hybrid ‘Netty’s Pride’ features a nearly black-purple center that transitions to creamy white tips. The ‘Purple Marble’ lily, an Asiatic type, is known for its solid, outfacing petals that lean toward burgundy. These true lilies grow from scaly bulbs to achieve their dark, dramatic coloring.
The Most Common Purple Look-Alikes
Many purple flowers share a similar aesthetic with true lilies. The Purple Calla Lily (Zantedeschia) is a popular choice, known for its sleek, deep purple to blackish-purple spathe wrapping around a central spadix. The Purple Peruvian Lily (Alstroemeria) features intricate, speckled inner petals and a bloom shape resembling a miniature lily. Purple Daylilies (Hemerocallis) are frequently mistaken due to their name and trumpet shape, but their blooms last only a single day. The Iris is another widespread purple flower often confused with lilies due to its elegant, upright form.
Distinguishing Features and Classification
Differentiating a true Lilium from its look-alikes requires observing specific anatomical details. True lilies have a flower structure composed of six identical tepals (three petals and three sepals that look alike). The leaves of a Lilium grow in a whorled or spiral pattern up a central, upright stem. Furthermore, all true lilies grow from a scaly underground bulb.
In contrast, look-alikes have distinct differences in anatomy and growth habit. The Calla Lily’s “flower” is actually a modified leaf called a spathe, and the plant grows from a thick underground stem called a rhizome. Daylilies grow from tuberous roots and feature long, grass-like foliage emerging directly from the base of the plant. They lack leaves spiraling up the flower stem. Observing these characteristics—the six identical floral segments, the scaly bulb, and the leaf arrangement on the stem—is the most reliable way to classify a plant as a true Lilium.