The Calla Lily (Zantedeschia) is recognized for its elegant, trumpet-shaped flowers and attractive, arrow-shaped foliage. A favorite for gardens and cut-flower arrangements, a common question is whether these blooms return each year. The answer depends on understanding the plant’s natural life cycle and providing the specific care needed to bridge the growing seasons.
Calla Lilies: Annuals, Perennials, or Tender Bulbs?
Calla Lilies are rhizomatous perennials, meaning they have the capacity to return and bloom year after year. They grow from a thick, underground stem structure called a rhizome, which stores energy. In their native, warm, tropical environment in southern Africa, they are true perennials, blooming continuously with a natural resting period.
This perennial nature is only maintained in climates with little to no frost (USDA Hardiness Zones 8 through 10). Outside of these zones, the rhizomes cannot survive freezing winter temperatures. In colder regions, Calla Lilies are treated as tender bulbs, requiring intervention for annual re-blooming. If left in the ground, they will not survive and must be replanted each spring.
Key Requirements for Successful Re-blooming
Proper care during the active growing season is necessary to ensure the rhizome stores enough energy for the following year’s flowers. Calla Lilies thrive in full sun but benefit from afternoon shade in regions with hot summers to prevent leaf scorching. They require rich, organically enhanced soil that is consistently moist but drains well to prevent rhizome rot.
Consistent moisture is important during foliage and flower development, as these plants are adapted to marshy areas. However, waterlogged soil leads to rhizome rot, making the balance between moist and well-drained soil delicate. During active growth, apply a balanced liquid fertilizer monthly to support foliage and flower production. Avoid fertilizers high in nitrogen, which encourage excessive leaf growth at the expense of blooms.
The Dormancy Period and Overwintering
Dormancy is a necessary part of the Calla Lily’s life cycle, allowing the plant to rest and gather energy reserves for the next season. This resting phase is triggered in the fall as the weather cools and flowering ceases. In zones colder than USDA Zone 8, overwintering the rhizome is the only way to achieve annual re-blooming.
To initiate dormancy, gradually reduce watering in mid-to-late fall after blooming ceases. This signals the plant to withdraw energy from its foliage and store it in the rhizome. Once the foliage has yellowed and died back, cut the leaves down to a few inches above the soil line.
If the plant is in the ground, the rhizomes must be dug up before the first hard frost, as freezing temperatures will destroy them. After lifting, gently brush off the soil. Allow the rhizomes to cure for seven to ten days in a dry, dark, well-ventilated area (60 to 70°F). Curing toughens the outer skin, protecting the rhizome during winter storage.
Store the dormant rhizomes in a cool, dry, dark location (40 to 50°F), such as a basement or garage. They can be placed in a paper bag or a box filled with dry peat moss or sand. This storage ensures the rhizome remains viable until replanting in the spring after the danger of frost has passed.