The calla lily (Zantedeschia) is a popular ornamental plant known for its striking, elegant, trumpet-shaped bloom (a modified leaf called a spathe). Originating in the warmer regions of Southern Africa, this plant grows from a fleshy underground stem called a rhizome. This guide helps select the optimal location and environment for planting your calla lily to ensure the best results.
Ideal Light and Climate Conditions
The planting location depends heavily on the climate, as Zantedeschia species are tender perennials. Calla lilies thrive year-round only in USDA Hardiness Zones 8 through 10, where they can be left in the ground. Gardeners in colder regions (Zones 3 through 7) must treat them as annuals or lift and store the rhizomes indoors before the first hard frost.
Sunlight requirements vary based on regional temperatures. In cooler northern climates, full sun (six or more hours daily) encourages prolific blooming. In regions with intense summer heat, the plant prefers partial shade, needing protection from the harsh afternoon sun. This prevents foliage scorching and helps extend the bloom period.
The plant requires consistent warmth (60 to 80 degrees Fahrenheit). Rhizomes should only be planted outdoors in spring once the danger of frost has passed and the soil temperature has warmed to a minimum of 65 degrees Fahrenheit. This promotes rapid establishment and minimizes the risk of rotting.
Preparing the Soil and Planting Depth
A successful planting site requires a growing medium that is rich in organic matter, consistently moist, and well-draining. While the calla lily tolerates moist conditions (especially the white-flowered Zantedeschia aethiopica), it will quickly succumb to rot if the soil remains waterlogged. The ideal soil pH for most colored hybrids is slightly acidic to neutral (6.0 to 7.0).
For heavy or clay soils, which retain too much moisture, the planting area must be amended. Incorporating compost, well-rotted manure, or peat moss improves soil structure and facilitates proper drainage. This organic material also supports the plant’s vigorous growth and flowering.
Once the soil is prepared, plant the rhizome horizontally at a depth of three to four inches. Orient the rhizome so the “eyes,” or small growing tips, face upward toward the soil surface. When planting multiple calla lilies, space them 12 to 18 inches apart to allow for mature growth and adequate air circulation.
Container Versus Garden Planting
Choosing between a garden bed and a container offers distinct advantages based on climate and gardening goals. Planting directly in the ground is the most labor-saving choice for gardeners in warmer Zones 8 to 10. The rhizomes can be left undisturbed to naturalize and rebloom annually. In-ground plants benefit from stable soil temperature and moisture, requiring less frequent watering than container plants.
Container planting offers the benefit of mobility, useful in colder regions. Potted plants can be easily moved to a sheltered location or brought indoors for overwintering, protecting the rhizomes from freezing. The container must have adequate drainage holes and be filled with a high-quality potting mix.
Container Maintenance
Container-grown calla lilies demand more attentive maintenance due to the limited soil volume. They require more frequent watering, as the potting mix dries out quickly, and benefit from regular feeding with a balanced, water-soluble fertilizer. For overwintering, allow the foliage to die back naturally after the first light frost. The entire pot or the dug-up rhizomes must then be stored in a cool, dry place until spring.