Calla Lilies, members of the Zantedeschia genus, are popular ornamental plants grown for their elegant, trumpet-shaped flowers. These plants grow from rhizomes, which are modified underground stems that store nutrients. After planting, a period of waiting is required before the first shoots emerge. Understanding the expected timeline helps gardeners manage expectations for spring planting.
The Typical Sprouting Timeline
The period between planting a calla lily rhizome and seeing the first sprout is variable, typically two to eight weeks. If environmental conditions are ideal, with sufficient warmth and moisture, emergence can occur quickly, sometimes in as little as 14 days. A longer wait, closer to the eight-week mark, often indicates the rhizome is taking more time to break dormancy in cooler or less-than-optimal soil.
Rhizomes must transition from dormancy into active growth before top growth is visible. Planting calla lilies in containers indoors before the last frost can accelerate this process, providing a head start. This method allows the rhizome to develop roots and shoots in a controlled, warm environment, leading to faster emergence compared to direct planting. For in-ground planting, the rhizome remains inactive until the soil temperature naturally rises enough to signal the growing season.
Environmental Factors Influencing Emergence
The most significant factor dictating emergence speed is the temperature of the surrounding soil. Calla lilies require a soil temperature of at least 60°F to 65°F to actively initiate shoot development. Planting before the soil reaches this minimum threshold results in a delay, as growth is paused until the necessary warmth is available. Cool soil is the primary inhibitor of early growth.
Consistent, managed moisture is necessary to encourage the rhizome to sprout. The soil should be kept evenly moist after planting to support rehydration. Overwatering before shoots emerge is a common mistake that can be detrimental. Saturated conditions can quickly lead to fungal issues and rot, preventing sprouting, since the newly planted rhizome is not yet actively drawing up large amounts of water.
Light exposure to the soil surface plays an indirect role in emergence. Full sun or partial sun exposure helps warm the soil to the optimal temperature range more rapidly than shaded locations. This increased thermal energy helps activate the physiological processes within the rhizome that drive sprout formation.
Troubleshooting Delayed Sprouting
If the expected sprouting window has passed, planting the rhizome too deep is a frequent error. This requires the emerging shoot to expend excess energy to reach the surface. Planting the rhizomes 2 to 4 inches deep is recommended, and exceeding this depth significantly hinders emergence. Reducing the soil depth slightly may encourage a delayed sprout to finally appear.
The viability of the rhizome should also be considered if no growth is observed. A healthy rhizome should feel firm and plump, not soft or shriveled, which suggests a loss of vitality or rot. Planting in cold soil, even if the rhizome was healthy, may have caused it to remain in deep dormancy.
Inspecting the soil for signs of excessive moisture is prudent, as the dormant rhizome is highly susceptible to bacterial soft rot in soggy conditions. If the rhizome is found to be soft and mushy upon inspection, it has succumbed to rot and will not sprout. Ensuring the rhizome was planted with its “eyes,” or growing points, facing upward is a final check that can sometimes resolve a non-emergence issue.