The Calla Lily (Zantedeschia) is a popular ornamental plant grown from a thickened underground stem called a rhizome, often mistakenly referred to as a bulb. Gardeners frequently ask how long it takes for these rhizomes to awaken and send up foliage. Under ideal conditions, the initial visible growth, or sprouting, typically occurs within two to eight weeks following planting. This wide range is heavily influenced by environmental conditions and the preparation of the rhizome itself.
The Expected Sprouting Window
The time it takes for a Calla Lily rhizome to sprout is usually between 14 and 60 days after planting. This duration is variable because the plant must first establish a healthy root system before dedicating energy to above-ground shoots. Sprouting is the emergence of the first visible shoot tip breaking the soil surface.
The species planted can slightly affect this timeline; large white varieties (Z. aethiopica) often sprout more readily than smaller, colored hybrids. The process requires consistent warmth and moisture to initiate metabolic activity within the dormant rhizome. Two weeks is considered fast, while two months suggests that conditions may not be ideal.
Preparing Bulbs for Successful Growth
Successful and timely sprouting begins with proper preparation of the rhizome. Inspect the rhizome to ensure it is firm and plump, indicating it is healthy and well-hydrated. Signs of softness, shriveling, or mold suggest the rhizome is compromised and should not be planted.
The rhizome must be oriented correctly when placed in the planting medium. Identify the “eyes,” which are small, raised growth points, and ensure these are facing upward. Soaking the rhizomes in lukewarm water for an hour or two before planting can help rehydrate the tissues and encourage dormancy breaking.
Key Environmental Factors Affecting Timing
The single most influential factor determining the speed of sprouting is the temperature of the soil. Calla Lilies require a consistently warm environment to stimulate growth. The soil temperature must be reliably above 60°F (15°C) for the rhizome to actively break dormancy and begin sending out shoots.
Planting in cooler soil will significantly extend the sprouting timeline, often delaying emergence by several weeks. Too-deep planting can also suppress and delay the appearance of the shoot, as the sprout must travel farther to reach the surface. Most sources recommend a planting depth of only two to four inches, with the growing tip barely covered. Consistent moisture is necessary to support the emerging root system, but the soil must be well-draining to prevent rot.
Why Sprouting May Be Delayed
When the expected two-to-eight-week window passes without any sign of growth, a few common issues are usually responsible for the delay. The most frequent cause is soil that is too cold, which simply keeps the rhizome in a state of suspended animation. If the soil has not maintained a temperature of at least 60°F, the plant will not begin to grow.
Excessive watering before the plant has developed leaves is another common cause of failure or delay. Since the rhizome is not yet actively transpiring moisture, overly saturated soil can lead to fungal issues and rot, effectively killing the plant before it has a chance to sprout. Conversely, if the rhizome dried out excessively during storage or if the soil has been allowed to become bone-dry after planting, the stored energy reserves may have been depleted. Lastly, a highly compacted or heavy clay soil can physically impede the delicate shoot from pushing its way to the surface.