The Calla Lily (Zantedeschia) is a popular ornamental plant recognized for its elegant, trumpet-shaped flowers called spathes. Originating from South Africa, these rhizomatous plants are highly valued in gardens and floral arrangements. How long a Calla Lily lasts outside is highly variable, depending on whether one refers to the life of the flower or the survival of the plant across seasons. Longevity is directly influenced by local climate conditions and the level of care received.
Duration of the Calla Lily Bloom
The longevity of the Calla Lily’s visible flower is impressive compared to many other garden blooms. An individual spathe, the colorful part of the flower, can remain attractive on the plant for several weeks. This long-lasting quality makes the plant desirable for continuous garden color throughout the summer. The overall bloom period for a single plant is extended, often lasting six to twelve weeks, depending on the specific cultivar and growing conditions.
The plant achieves this extended display by producing successive flowers over the season rather than blooming all at once. Providing ample light, consistent moisture, and appropriate temperatures encourages the development of new flower stalks, ensuring a longer period of appeal.
Calla Lily Seasonal Survival
The true lifespan of the Calla Lily plant outside is determined by its ability to survive winter dormancy, which is dictated by the local climate. As a tender perennial, the plant grows from a fleshy underground structure called a rhizome and is naturally hardy only in warmer regions. Calla Lilies are reliably perennial and can be left in the ground year-round in USDA Hardiness Zones 8 through 10. In these warm zones, the plant dies back as temperatures drop, but the rhizome survives the mild winter and regrows in the spring, potentially lasting for many years.
The rhizomes are sensitive to freezing and will be damaged or killed if the soil temperature falls below 25°F. In colder zones, particularly Zone 7 and below, Calla Lilies cannot withstand harsh winter temperatures. Here, the plant is often treated as an annual, limiting its lifespan to a single growing season from spring to the first hard frost. To preserve the plant and achieve multi-year survival in regions with freezing winters, the rhizomes must be actively managed by lifting and storing them indoors.
Maximizing the Plant’s Lifespan
Extending the Calla Lily’s life relies on specific maintenance practices focused on plant health and dormancy preparation. Consistent watering is necessary during the active growing season, as the plant prefers evenly moist but not soggy soil to prevent rhizome rot. A bi-weekly feeding schedule with a balanced liquid fertilizer throughout the blooming period supports continuous flower production. Removing spent flowers, a process called deadheading, should be done by gently pulling the entire flower stalk away from the base.
This directs the plant’s energy toward producing new blooms and strengthening the rhizome instead of seed production. In zones that experience freezing, the process of preparing for dormancy must begin after the foliage naturally yellows and before the first hard frost. The rhizomes must be carefully dug up to avoid damage, and the remaining foliage should be cut back to just a few inches above the bulb. After a brief curing period of a few days in a warm, dry location, the rhizomes are stored. Storing them in a cool, dark, and dry environment, such as a basement or garage, at a temperature around 50°F, prevents freezing and allows the plant to rest, ensuring viability for replanting the following spring.