The Zantedeschia species, commonly known as the Calla Lily, is celebrated globally for its striking, trumpet-shaped flowers, or spathes. Native to southern Africa, this plant grows from a fleshy underground stem called a rhizome rather than a true bulb. Calla Lilies are highly adaptable and can be grown successfully as a tender perennial outdoors or as a container plant indoors, though the required care differs based on the local climate and cultivation method.
Cultivating Calla Lilies Outdoors
Calla Lilies thrive outdoors as perennials only in warmer climates, specifically USDA hardiness zones 8 through 10. In these regions, the rhizomes remain in the ground year-round, dying back in winter and regrowing each spring. In colder zones (7 and below), the plant must be treated as a seasonal annual, or the rhizomes must be lifted and stored before the first hard frost.
The ideal outdoor location offers full sun exposure in cooler northern areas, or partial shade where summers are intensely hot. Providing afternoon shade in warmer climates prevents the foliage from scorching and keeps the plant hydrated. Successful outdoor growth requires a rich, well-draining medium amended with organic matter like compost.
Plant the rhizomes in spring after the danger of frost has passed, positioning them three to four inches deep with the growing tips facing upward. The plant requires consistent moisture, often facilitated by applying a layer of mulch to conserve soil water. While Calla Lilies need ample water, the soil must never become waterlogged, which can lead to root rot.
Growing Calla Lilies as Houseplants
Maintaining a Calla Lily indoors requires careful attention to light and temperature, replicating its native subtropical environment. The plant flourishes in bright, indirect light for most of the day, such as near an east- or north-facing window. Direct sun exposure, particularly intense midday light, can scorch the foliage and must be avoided.
Selecting the right container is important for indoor success, as it must have adequate drainage holes to prevent excess water accumulation. A standard, well-draining potting mix, often including amendments like perlite or coarse sand, provides the necessary aeration and moisture retention. The optimal temperature range for active growth is between 60 and 80 degrees Fahrenheit. Keep plants away from heating or cooling vents, which cause sudden temperature fluctuations or drying drafts.
Calla Lilies appreciate higher humidity levels, which can be challenging to provide in a typical home environment. Placing the potted plant on a shallow tray filled with pebbles and water allows for beneficial local evaporation without the pot sitting directly in water. Misting the foliage offers a temporary boost in humidity.
Managing Watering, Feeding, and Dormancy
During the active growing and flowering season, Calla Lilies require consistent moisture; the soil should be kept continuously damp but never soggy. Check the top inch of the soil, and when it feels dry to the touch, thoroughly water the plant. Container plants, especially, require more frequent watering than those planted directly in the ground, as their soil dries out faster.
To support flower production, the plant benefits from regular feeding every two to four weeks during spring and summer. Apply a balanced liquid fertilizer, such as a 10-10-10 or one formulated for blooms, diluted to half the recommended strength to prevent chemical burn. Stop fertilization entirely once the flowering period concludes and the plant begins to slow its growth.
The Calla Lily requires a period of dormancy to rebloom reliably the following season. After the flowers fade, the foliage naturally begins to yellow and die back, and watering should be gradually reduced and eventually stopped.
Indoor Dormancy
For indoor plants, this dormant period lasts two to three months. Move the pot to a cool, dark, and dry location with temperatures below 50 degrees Fahrenheit but above freezing.
Outdoor Rhizome Storage
In colder outdoor gardens, the rhizomes must be dug up before the first frost. Allow them to air-dry for several days, and then store them in a cool, dry medium like peat moss until replanting the following spring.