The Calla Lily, belonging to the genus Zantedeschia, is a rhizomatous perennial native to the wetlands of southern Africa. Despite its common name, it is not a true lily but is part of the Araceae family. Its signature structure is the inflorescence, consisting of a large, trumpet-shaped, modified leaf called the spathe, which wraps around a central spike called the spadix. This plant is highly adaptable, thriving both as a seasonal garden addition and as a permanent indoor container plant, depending on the local climate and care provided.
Outdoor Cultivation Requirements
Calla Lilies perform best when planted in rich, organically amended, and well-draining soil. Consistent moisture is necessary for healthy growth, as the plant naturally grows along stream banks and marsh edges, but waterlogging must be avoided to prevent rhizome rot. Optimal placement depends significantly on the regional climate, balancing the need for light with protection from intense heat.
In cooler climates (USDA Hardiness Zones 3 through 7), full sun is preferred to maximize blooming potential and ensure the soil warms sufficiently. In warmer regions (Zones 8 through 10), the plant benefits from partial shade, especially during intense afternoon heat, which prevents scorch. It is a tender perennial, reliably winter-hardy only in Zones 8 and above, as it is susceptible to frost damage. When planting rhizomes outdoors, place them about four inches deep with the growing tips facing upward, ensuring the soil temperature is at least 65°F after the last frost.
Indoor Container Care
When kept as a houseplant, the Calla Lily requires bright, warm conditions. It thrives in locations that receive bright, indirect or diffused light for at least six hours daily, such as near a sheer-curtained window. While direct sun promotes blooming, intense midday light should be avoided as it can scorch the foliage and fade the spathe colors.
The ideal indoor temperature range for sustained growth is between 60°F and 75°F; situate the plant away from drafts or vents that cause sudden temperature fluctuations. Proper watering is essential, requiring the soil to be kept consistently moist but never soggy to prevent root issues. Use a high-quality, peat-based potting mix that drains quickly and a container with adequate drainage holes to maintain this balance.
Seasonal Movement and Dormancy
In regions where winter temperatures drop below freezing, Calla Lilies grown in garden beds must be lifted and prepared for indoor storage. This process begins after the first light frost causes the foliage to yellow and die back, signaling the rhizomes have stored enough energy for dormancy. After digging up the rhizomes, trim the remaining foliage to about two inches, and allow the rhizomes to dry in a sheltered, dark place for a few days to cure.
For storage, place the dried rhizomes in a ventilated container filled with a dry substrate like peat moss or vermiculite. Keep them in a cool, dark, and frost-free location, ideally between 40°F and 55°F, to ensure a successful dormancy period of at least two to three months. Indoor plants also require dormancy after blooming; induce this by minimizing water and allowing the foliage to yellow before moving the pot to a cool, dark place until spring growth resumes.