The Calla Lily, a popular ornamental plant, belongs to the genus Zantedeschia, celebrated for its distinctive, elegant floral structure. What is commonly called the flower is actually a modified leaf, called a spathe, which wraps around a central spike known as the spadix. This unique trumpet or funnel shape makes the Calla Lily a valued choice for sophisticated floral arrangements and as a striking specimen in the home garden. Zantedeschia is a perennial plant that grows from underground storage organs, either rhizomes or tubers.
Native Origins and Geographic Spread
The Zantedeschia genus originates exclusively from the southern regions of Africa, specifically throughout South Africa, Lesotho, Eswatini, and extending northeast into Malawi. The plants thrive in areas with pronounced seasonal rainfall, with their native habitats ranging from grasslands and savannahs to the fynbos biome. The white-flowered species, Zantedeschia aethiopica, is often found naturally growing in moist environments like stream banks and marshy areas, sometimes even in shallow water.
This genus was introduced to Europe as early as the 17th century, where it quickly gained popularity for cultivation in botanical gardens and greenhouses. Calla Lilies have since become naturalized in many regions across the globe, including parts of western Europe, New Zealand, Australia, and coastal California. In these areas, the plant now grows in the wild, sometimes aggressively, forming dense colonies in wetlands and coastal prairies. Finding a Calla Lily in the wild outside of Africa is typically a sign of this geographic spread.
Sourcing Calla Lilies for the Home Garden
Gardeners looking to cultivate Calla Lilies have a few main options for acquiring plant material, depending on their desired timeline and variety. The two primary forms available for planting are the dormant underground structures: rhizomes, which are characteristic of the large white Zantedeschia aethiopica, and tubers, which produce the vibrant, colored hybrids. These dormant “bulbs” are typically sold in late winter and early spring by local garden centers, online specialty bulb vendors, and mail-order catalogs, providing the most cost-effective way to start a large collection.
For those seeking more immediate results or a guaranteed color match, established potted plants are available for purchase throughout the spring and summer at nurseries and big-box retailers. Buying a potted plant allows for immediate placement in the garden or on a patio, bypassing the initial several weeks of growth required for a dormant rhizome to sprout. Calla Lilies are also widely available as cut flowers from florists and grocery stores, often year-round, for those who only wish to enjoy their beauty in an arrangement.
Optimal Placement for Cultivation
Selecting the correct location in the garden is paramount for successful cultivation, as Calla Lilies require a specific combination of light, soil, and moisture. The ideal placement balances the need for adequate light to promote flowering with the risk of scorching foliage in intense heat. Generally, they prefer a position that receives full sun to partial shade, with colored varieties often blooming best with at least six hours of direct sun per day. However, in climates with very hot afternoon sun, a spot with dappled or afternoon shade is preferable to prevent the foliage from burning.
The soil composition must be rich in organic matter to provide the necessary nutrients and retain moisture, yet it must also be exceptionally well-draining to prevent the rhizomes or tubers from rotting. A slightly acidic to neutral soil pH, ideally between 6.0 and 6.5, is optimal for nutrient uptake and overall plant health. For the moisture-loving white Zantedeschia aethiopica, a location near a pond or a spot that remains consistently moist is beneficial, and this variety can even be grown as a marginal aquatic plant in shallow water.
The colored hybrid varieties are generally less tolerant of consistently soggy conditions than the white species and require more attention to drainage. A regular watering schedule is necessary during the active growing season, ensuring the soil remains moist but never waterlogged. Incorporating a layer of compost or mulch around the plants helps to maintain soil moisture and keep the root zone cool.
Handling and Toxicity Information
When handling Calla Lilies, it is important to be aware of their toxicity to both humans and pets. All parts of the plant, including the leaves, stems, and underground rhizomes or tubers, contain insoluble calcium oxalate crystals. These microscopic, needle-shaped structures, known as raphides, are contained within specialized plant cells.
If any part of the plant is chewed or ingested, the raphides are forcefully ejected, causing immediate and intense localized irritation. This reaction results in a burning sensation in the mouth and throat, excessive drooling, and possible swelling. Gardeners should wear gloves when dividing or planting the rhizomes and ensure the plants are placed in a location inaccessible to children and household animals to prevent accidental ingestion.