The Calla Lily, botanically known as Zantedeschia, is a striking plant celebrated for its elegant, sculptural flowers and lush, arrow-shaped foliage. Originating from southern Africa, this species is popular globally, gracing both indoor spaces as a potted plant and outdoor gardens as an impressive border specimen. Many people wonder if they can successfully grow this tropical beauty outside year after year, and the answer is yes, but the feasibility depends almost entirely on where you live. This plant is grown from a fleshy underground stem called a rhizome, and its survival outdoors is directly linked to regional climate conditions.
Determining Feasibility Based on Climate
Growing Calla Lilies as a perennial, meaning they return each spring, depends primarily on the minimum winter temperatures in your region. These plants are considered frost-tender and are reliably perennial only in the warmer parts of the country. Specifically, the Zantedeschia rhizomes can typically survive the winter outdoors in USDA Hardiness Zones 8 through 10 or 11, where the average minimum temperature does not drop below 10°F to 20°F.
If your area falls within these warmer zones, the Calla Lily can remain in the ground during its dormancy period and re-emerge in the spring. In colder zones (Zone 7 and below), the plant must be treated differently to ensure survival. In these regions, the Calla Lily must be grown as a summer annual, or its rhizomes must be lifted before the first hard frost to protect them from freezing temperatures.
Site Selection and Soil Preparation
Once the climate is determined suitable, selecting the proper location is the next step for a thriving Calla Lily. These plants perform best in a site that receives full morning sun but is protected from intense, scorching afternoon sun, especially in regions with hot summers. Partial shade is often the ideal exposure, as too much direct sun can sometimes cause the leaves to burn or scorch.
The soil composition is equally important, as Calla Lilies prefer a rich, organically enhanced, and consistently moist environment. Although they require consistent moisture, the soil must be well-draining to prevent rhizomes from sitting in standing water, which leads to rot. If the soil is heavy clay or lacks organic matter, amend it generously with materials like compost or peat moss. This improves drainage and nutrient retention, creating the loose, fertile medium needed for healthy growth.
Planting Techniques and Seasonal Care
Planting rhizomes is best done in spring after all danger of frost has passed, ideally when the soil temperature reaches at least 65°F. The rhizomes should be placed with the growing tips, or “eyes,” facing upwards and planted approximately 2 to 4 inches deep. A spacing of about 12 to 18 inches between each rhizome allows for adequate air circulation and growth as the plant matures into a clump.
Following installation, consistent and generous watering is the most important aspect of seasonal care. The soil should remain evenly moist throughout the active growing season, though care must be taken to avoid a waterlogged condition that promotes root diseases. Monthly feeding with a balanced liquid fertilizer supports robust foliage and flower production. Faded blooms should be removed by pulling the entire stem from the base, redirecting energy toward new flower development.
Winterizing and Handling Dormancy
Calla Lilies require a period of dormancy at the end of the growing season, and winterizing depends entirely on the hardiness zone. In milder climates, specifically Zone 8 and warmer, the rhizomes can remain in the ground to overwinter. To protect them, stop watering in the fall to encourage dormancy, cut back the naturally dying foliage, and apply a thick, 4-inch layer of mulch over the planting area.
For gardeners in Zone 7 and colder, the rhizomes must be lifted and stored indoors to prevent freezing. After the first light frost kills the foliage, gently dig up the rhizomes, brush off excess dirt, and allow them to cure in a warm, dry, well-ventilated location for about a week. Once cured, store the rhizomes in a cool, dark, dry environment (40°F to 50°F), such as a basement or garage, nestled in a medium like peat moss or vermiculite until spring.