The Calla Lily (Zantedeschia) is a popular ornamental plant native to Southern Africa, recognized for its elegant, trumpet-shaped flowers called spathes. These distinctive blooms come in a wide array of colors. While commonly referred to as a bulb, the Calla Lily grows from a rhizome, a modified underground stem used for nutrient storage. Successfully establishing this plant requires careful attention to the planting process to facilitate healthy growth and abundant flowering. This guide offers precise instructions for planting the Calla Lily rhizome.
Choosing the Right Conditions
The long-term health of the Calla Lily is determined by the environment established before planting. Timing is paramount, as these tender perennials cannot tolerate frost. Planting should be delayed until late spring or early summer, after the final threat of frost has passed and the soil temperature has warmed to at least 65°F.
The ideal location provides full sun in cooler climates or partial shade in regions with intense summer heat. Too much shade can cause the plant to prioritize foliage growth over flower production.
Optimal soil is rich in organic matter and exceptionally well-draining. Poor drainage is the primary cause of failure, leading quickly to rhizome rot. If the soil is heavy, amend it with compost or other organic material to improve porosity. While Calla Lilies enjoy consistent moisture, the soil must never become soggy.
Planting Depth and Orientation
The placement of the rhizome within the prepared planting site is critical. The recommended planting depth is approximately two to four inches, measured from the top of the rhizome to the soil surface. This depth provides necessary insulation and stability while allowing shoots to emerge efficiently.
When planting multiple rhizomes, adequate spacing is required for mature growth and proper air circulation, which helps prevent fungal issues. Space rhizomes 12 to 18 inches apart. Planting them too closely restricts the development of the plant’s foliage and diminishes flowering.
Proper orientation encourages efficient sprouting. The rhizome should be set with the “eyes,” or small, pointed growth tips, facing upward toward the soil surface. While the plant may still grow if planted incorrectly, it expends more energy to correct its growth trajectory, potentially delaying foliage and blooms. After setting the rhizome, gently backfill the hole with soil.
Establishing the Calla Lily
Immediately following placement, thoroughly soak the planting area. This initial watering settles the earth around the rhizome and eliminates air pockets. Water gently to avoid disturbing the newly placed rhizome.
After this initial saturation, water sparingly until the first shoots of foliage become visible. Overwatering before the plant develops a root system can lead to rot. Once several leaves emerge, the plant enters its active growth phase, requiring consistent moisture to thrive.
During the growing season, keep the soil evenly moist, especially in warmer periods. Fertilization can begin once active growth is underway. Use a balanced liquid fertilizer every two to four weeks, or apply a slow-release granular fertilizer at the start of the season. Avoid fertilizers high in nitrogen, which promote excessive leaf growth at the expense of blooms.
Preparing for Dormancy
As the growing season concludes, Calla Lilies naturally enter a period of dormancy, which is necessary for their rejuvenation and subsequent year’s flowering. The transition is signaled by the yellowing and browning of the foliage in late fall. Once this process begins, gradually reduce watering to induce the dormancy period.
Warm Climates (Zones 8-10)
In warm climates (USDA Zones 8 through 10), the rhizomes can remain in the ground over winter. In these regions, allowing the foliage to die back naturally and then cutting it down to soil level is sufficient preparation. A layer of mulch can be applied to the planting site to provide insulation and protect the rhizomes from temperature fluctuations.
Cold Climates (Zone 7 and Below)
For colder regions (Zone 7 and below), the rhizomes must be lifted and stored indoors to prevent freezing. After the foliage has been killed by the first frost, the rhizomes should be carefully dug up, gently cleaned of excess soil, and allowed to cure in a warm, dry area for several days. The cured rhizomes are then stored over winter in a cool, dark location, ideally around 50°F, nestled in a medium like peat moss or sawdust to maintain a stable, slightly dry environment until they are replanted the following spring.