Picture: Calla Lily growing in pots
Calla lilies (Zantedeschia spp.) are elegant, sophisticated flowering plants native to southern Africa, particularly South Africa and Lesotho. Despite their common name, they are not true lilies — they belong to the family Araceae, making them relatives of peace lilies, anthuriums, and elephant ears. The genus Zantedeschia contains about eight species, and from these, numerous stunning hybrid cultivars have been developed. They have been admired and cultivated for centuries and today hold a prominent place in both garden horticulture and the global cut flower industry.
The most iconic feature of the calla lily is its elegant, funnel-shaped spathe — the smooth, waxy, petal-like structure that wraps around the finger-like spadix at the flower’s centre. What most people think of as the “flower” is actually this modified leaf, or spathe, which comes in a remarkable range of colours including pure white, cream, yellow, orange, pink, deep red, burgundy, and near-black purple. The true flowers are the tiny, inconspicuous structures clustered along the spadix itself. The foliage is equally attractive — large, arrow-shaped, glossy green leaves, often decorated with translucent white spots in many cultivars.
There are two broad groups of calla lilies that gardeners work with. The common or arum calla (Zantedeschia aethiopica) produces the classic large white blooms and is the most cold-tolerant of the genus, capable of surviving mild frosts and thriving in boggy conditions. The coloured or summer callas — derived from species such as Z. rehmannii, Z. elliottiana, and their hybrids — produce the full rainbow of colours and are more tender, preferring drier conditions between growing periods and requiring frost protection in most climates.
Calla lilies grow from fleshy underground rhizomes, and in suitable climates they are reliably perennial, returning and spreading each year. In frost-prone regions, the rhizomes of the coloured varieties must be lifted and stored indoors over winter, while the white Z. aethiopica can often be left in the ground with a protective mulch. They thrive in partial to full sun, though in very hot climates some afternoon shade is beneficial. Rich, moisture-retentive soil with good drainage suits them well, and they perform equally beautifully in garden beds, borders, and containers.
Beyond the garden, calla lilies hold deep cultural and symbolic significance. White calla lilies are strongly associated with purity, rebirth, and sympathy, making them a staple in wedding bouquets and funeral arrangements across many cultures. They have also been immortalised in art — most famously in the paintings of Diego Rivera and Georgia O’Keeffe — and remain one of the most recognised and beloved floral symbols in the world. Their long, sturdy stems and long vase life make them among the most prized cut flowers in the florist trade globally.
One important note for gardeners with children or pets is that all parts of the calla lily plant contain calcium oxalate crystals, which are toxic if ingested and can cause skin irritation upon contact with the sap. Despite this, with sensible handling they pose no practical danger in the garden. They are relatively low-maintenance plants that reward attentive care with a breathtaking floral display, and their combination of refined elegance, bold foliage, and wide colour range makes them a truly exceptional addition to any garden setting or home interior.
Picture: Calla Lily Seeds
How to Grow Calla Lily from Seed
1. Growing calla lilies from seed is considerably more challenging and time-consuming than growing them from rhizomes, and it is not the method most commonly used by home gardeners. However, it is a rewarding process that allows for the possibility of raising new colour variations and is the best way to produce large numbers of plants economically. Patience is essential, as seed-grown callas can take two or more years to produce their first bloom.
2. Obtain fresh, viable seed, as calla lily seeds lose viability relatively quickly. The freshest seed gives the best germination rates. Seeds can be harvested from pollinated seed pods on existing plants once the pods turn soft and yellowish-green, or they can be purchased from specialist orchid and exotic plant seed suppliers who deal in fresh stock.
3. Extract and clean the seeds carefully. Calla lily seeds are contained in fleshy berry-like fruits. Squeeze the seeds out of the pulp, then rinse them thoroughly under running water to remove all traces of the surrounding gel, which contains germination-inhibiting compounds that will reduce success rates if left on the seed.
4. Soak the cleaned seeds in lukewarm water for 12 to 24 hours before sowing. This softens the outer seed coat and begins the hydration process that triggers germination. Discard any seeds that float after soaking, as they are unlikely to be viable, and proceed with those that have sunk to the bottom of the soaking vessel.
5. Prepare a suitable growing medium before sowing. Use a fine, sterile seed-starting mix or a blend of peat moss and perlite in equal parts. The mix should be light, well-aerated, and moisture-retentive without becoming waterlogged — calla seeds are prone to rotting in overly heavy or saturated conditions.
6. Sow seeds at a shallow depth of no more than 1 cm (about half an inch) below the surface of the moist growing medium. Space seeds at least 3 to 4 cm apart if sowing in trays, or sow one seed per individual small pot or cell. Firm the surface lightly after sowing to ensure good seed-to-medium contact.
7. Cover the seed tray or pots with a clear plastic dome or plastic wrap to maintain high humidity around the seeds. Calla lily seeds require consistently moist conditions to germinate and must never be allowed to dry out during this critical period. Check the moisture level daily and mist lightly with a spray bottle as needed.
8. Provide warm temperatures throughout the germination period. Calla seeds germinate best at temperatures between 18 and 24°C (65–75°F). A seedling heat mat placed beneath the trays is helpful, particularly if you are sowing during cooler months. Avoid temperatures that fluctuate widely, as inconsistency can delay or prevent germination.
9. Place the covered trays in a warm location with bright, indirect light during germination. Direct harsh sunlight at this stage can overheat the tray and damage the seeds or emerging seedlings. A bright windowsill shielded from direct midday sun, or a position under a grow light on a timer, works very well.
10. Expect germination to be slow and uneven. Calla lily seeds typically take anywhere from two to eight weeks to germinate, and not all seeds in a batch will sprout at the same time. Do not discard the tray if germination appears slow — continue providing warmth and moisture and check regularly for new sprouts over several weeks.
11. Once seedlings emerge and show their first true leaf, remove the plastic cover to improve air circulation and reduce the risk of damping off. Begin transitioning seedlings to brighter light gradually — introducing them to more direct light over the course of a week to avoid scorching the tender young leaves.
12. Transplant seedlings into individual pots once they are large enough to handle comfortably, typically when they have two to three true leaves. Use a rich, well-draining potting mix and choose pots with good drainage holes. Handle the delicate roots with great care during transplanting to minimise root disturbance and setback.
13. Water seedlings consistently but carefully. Calla lilies prefer evenly moist soil and are sensitive to both drought and waterlogging. Allow the top centimetre of the growing medium to dry slightly between waterings, but never allow the soil to dry out completely, particularly in the active growing phase while plants are young and establishing.
14. Begin a gentle feeding programme once seedlings are actively growing and have been in their individual pots for two to three weeks. Use a balanced liquid fertiliser at half the recommended strength every two weeks. As the plants develop further, gradually increase to full strength and switch to a fertiliser with a higher potassium content to support root and flower development.
15. Harden off seedlings carefully before moving them outdoors. Over a period of 10 to 14 days, gradually introduce them to outdoor conditions — beginning with a few hours of sheltered, indirect outdoor light per day and increasing exposure progressively. This acclimatisation process is important for preventing transplant shock and leaf scorch when plants make the transition to the garden.
16. Transplant seedlings to their final garden position or outdoor containers only after all frost risk has completely passed and temperatures are consistently warm. Choose a site with partial to full sun, rich and moisture-retentive but well-draining soil, and shelter from strong wind. Be prepared to wait — seed-grown calla lilies typically take one to two full growing seasons before producing their first magnificent bloom, but the wait is well worth the effort.