Asiatic lilies are reliable, brightly colored additions to a garden, and they return each year. These hybrids are true lilies that fall into the category of herbaceous perennials, meaning their root structure survives underground through the winter. They are celebrated for their strong, upright stems holding numerous star-shaped or bowl-shaped blooms in a spectrum of colors from soft pastels to fiery reds and oranges. Reaching heights of two to five feet, Asiatic lilies are popular for their early summer display and are relatively easy to cultivate.
What Makes Asiatic Lilies Perennial
The Asiatic lily’s ability to return annually lies in its specialized underground storage structure, known as a bulb. Unlike a tulip, the lily bulb is scaly, composed of tight, fleshy, overlapping scales that lack a protective outer skin. This scaly bulb serves as the plant’s reservoir, storing starch and soluble sugars produced by the foliage during the growing season.
This stored energy is protected underground during the cold months, fueling the plant’s survival through dormancy. The plant thrives best in USDA Hardiness Zones 4 through 9. In these zones, ground temperatures are cold enough to satisfy the bulb’s dormancy requirements but not so cold as to freeze the bulb solid and cause tissue damage.
Essential Care for Winter Survival
Preparing Asiatic lilies for winter maximizes the energy stored in the bulb for the next growing season. The most important step is resisting the urge to cut back the foliage immediately after the flowers have faded, as the green leaves must remain intact to continue photosynthesizing and replenishing the bulb’s energy reserves.
Wait until the foliage naturally turns yellow or brown and dies back completely in the late fall or early winter before pruning. Once the plant has transferred all usable energy back to the bulb, the spent stems can be cut down to the ground. Proper drainage is also important for winter survival, as Asiatic lily bulbs can rot if they sit in cold, waterlogged soil.
In colder climates, applying a protective layer of winter mulch helps insulate the bulbs and stabilize the soil temperature. Organic materials like straw, pine needles, or shredded leaves should be spread about two to three inches deep over the planting area after the ground begins to freeze. This mulch prevents cycles of freezing and thawing, which can heave the bulbs out of the ground and damage the roots.
Maintenance for Abundant Future Blooms
Care after the blooming period focuses on ensuring maximum energy storage for a vigorous return the following year. This is achieved through deadheading, which involves removing the spent flower heads from the stem. Deadheading prevents the plant from expending energy on developing seeds, redirecting those resources back into the bulb.
When deadheading, only the faded flower should be snipped off, leaving the main stem and all the leaves intact. Over time, Asiatic lilies multiply, creating a dense clump of bulbs that compete for limited nutrients, space, and moisture. This overcrowding can eventually lead to a decrease in the size and number of flowers produced.
To maintain robust flowering, the bulbs should be divided every three to five years. This involves gently lifting the entire clump in the fall after the foliage has died back and separating the smaller offset bulbs from the main mother bulb. Replanting these separated bulbs gives them the necessary space to grow and ensures the continuation of abundant, high-quality blooms.