The Calla Lily (Zantedeschia) is a popular ornamental plant recognized for its unique spathe-and-spadix flower structure. Growers propagate this perennial to increase stock or to rejuvenate a parent plant that has become overcrowded. The most effective technique for multiplying Calla Lilies involves dividing the underground storage structure, known as the rhizome. This method uses the plant’s natural ability to sprout new growth from separate sections.
Timing and Necessary Tools
The optimal time to divide Zantedeschia rhizomes aligns with the plant’s dormant cycle to ensure minimal stress. This period typically occurs in late fall after the foliage dies back or in early spring just before new growth emerges. Working during dormancy allows the plant to focus energy reserves on healing and establishing new root systems rather than supporting active leaf production.
Gathering the appropriate tools beforehand simplifies the propagation process and maintains plant health. A sharp, sterilized cutting instrument, such as a knife or bypass pruners, is required for making clean cuts through the dense rhizome material. Sterilization, often achieved by wiping the blade with rubbing alcohol, prevents the transfer of fungal pathogens or bacteria.
New, clean containers and a well-draining potting mix should be prepared for immediate planting. Gardeners should wear protective gloves, as the Calla Lily sap contains calcium oxalate crystals, which can cause skin irritation. Having all materials ready minimizes the time the rhizomes are exposed to the air, reducing the risk of desiccation.
Dividing the Rhizome Step-by-Step
The process begins with the careful excavation of the parent Calla Lily plant from its soil. Use a garden fork or trowel to gently loosen the surrounding soil, digging wide enough to avoid slicing into the rhizome mass. Once lifted, the entire clump should be gently shaken or rinsed with water to remove excess dirt and clearly expose the rhizome structure.
Thorough inspection of the exposed rhizome is necessary, looking specifically for small, pointed structures known as “eyes” or growth points. These eyes indicate the location where new shoots and roots will emerge. The rhizome tissue itself should appear firm and healthy, without any signs of rot or soft spots.
Using the sterilized knife, the rhizome is cut into smaller sections suitable for replanting. Each section must retain at least one viable growth eye. The size of the division is less important than the presence of this growth point; however, larger sections generally produce more robust new plants sooner.
After separation, the newly cut surfaces are susceptible to infection from soil-borne pathogens. To mitigate this risk, the divisions should be allowed to dry in a cool, shaded area for several hours. This encourages the formation of a protective layer known as a callus. Some gardeners choose to lightly dust the open wounds with a commercial fungicide or sulfur powder before drying for added protection. The callusing process seals the wound against moisture loss and microbial entry.
Post-Propagation Care for New Shoots
Once the cut surfaces have sufficiently callused, the new rhizome divisions are ready for planting in their prepared containers or garden space. The planting depth is shallow, with the top of the rhizome placed just one to two inches beneath the soil surface. The well-draining potting mix is important to prevent water accumulation around the rhizome, which is the primary cause of rot.
Initial watering should be done sparingly, providing just enough moisture for the soil to settle around the divisions. Overwatering at this stage is detrimental because the rhizome lacks an established root system, increasing the risk of fungal infection. Divisions should only receive regular watering once the first signs of new shoot growth become visible above the soil line.
The containers should be placed in a sheltered location that receives bright, indirect sunlight or dappled shade. Direct, intense sunlight can stress the unrooted divisions and cause excessive moisture loss. Maintaining a consistently warm soil temperature, ideally between 60°F and 75°F, encourages root development and shoot emergence.
Patience is required when establishing new Calla Lily divisions, as robust top growth and flowering will not occur immediately. The plant must first expend energy on root formation before dedicating resources to foliage and flower production. While smaller leaves may appear quickly, a full-sized plant capable of producing the characteristic spathe flower is generally not expected until the following growing season.