Propagating Calla Lilies and Arum Lilies: Division of Rhizomes and Other Methods

Introduction

Calla lilies (Zantedeschia spp.) and Arum lilies are cherished for their stunning, elegant flowers. Propagating these plants can ensure a continuous supply of these beautiful blooms. This comprehensive guide focuses on propagation methods, particularly the division of rhizomes, while incorporating all relevant information for successful cultivation.

Propagation Methods

Division of Rhizomes

One of the most effective methods for propagating Calla and Arum lilies is through the division of rhizomes. This method is typically performed in the spring when the plants are coming out of dormancy.

• Preparation: Carefully dig up the mature plant to expose the rhizomes. Handle the plant gently to avoid damaging the rhizomes.
• Division Process: Cut the rhizomes into sections, ensuring each section has at least one visible bud. Small rhizomes that have been overwintered in pots can be divided similarly.
• Planting: Plant the divided rhizomes 5 cm deep in well-prepared soil. Space the sections about 30 to 40 cm apart to allow adequate room for growth.

Seed Propagation

Although slower, seed propagation is another viable method for propagating Calla and Arum lilies.

• Sowing Seeds: Sow the seeds at a depth of 5 cm, spaced 8 cm apart. It is best to start seeds indoors to control the growing environment.
• Temperature and Conditions: Maintain a temperature of around 20°C to encourage germination. The seeds usually take 1 to 3 months to germinate.
• Transplanting: Once the seedlings are strong enough and the risk of frost has passed, transplant them into the garden. Ensure the soil is well-prepared and enriched with compost.

Soil and Planting Requirements

Soil Preparation

Proper soil preparation is crucial for the healthy growth of Calla and Arum lilies.

• Soil Type: These lilies thrive in well-composted, loose, free-draining soil. The soil should be rich in humus and organic matter, with a slightly acidic to neutral pH of 6.0 to 6.5.
• Compost Application: Incorporate generous amounts of well-decomposed compost into the soil to enhance fertility and moisture retention.
• Planting Holes: Prepare planting holes that are about 5 cm deep for rhizomes and bulbs. Ensure adequate spacing to allow for air circulation and growth.

Environmental Conditions

Temperature and Light

Arum lilies prefer a semi-shaded environment, especially where there is no permanent water nearby, while Calla lilies can tolerate full sun near water sources.

• Daytime Temperature: Maintain a daytime temperature of around 18°C.
• Nighttime Temperature: Keep nighttime temperatures around 16°C. These plants do not tolerate severe frost, so appropriate measures should be taken to protect them in colder climates.

Watering and Irrigation

Consistent watering is essential, especially during the vegetative leaf growth phase.

• Irrigation Systems: Drip and overhead irrigation systems can help maintain soil moisture levels. Avoid overwatering as it can lead to root rot and other fungal diseases.
• Senescence Phase: As the plant enters senescence, gradually reduce watering to prepare it for dormancy.

Fertilization

• Active Growth: During active growth phases, apply a high-nitrogen fertilizer every two weeks to support foliage development.
• Post-Flowering: After flowering, switch to a high-potassium fertilizer once a week to encourage strong rhizome development.
• Slow-Release Fertilizers: Using a balanced slow-release fertilizer in spring and summer can provide a steady nutrient supply.

Pest and Disease Management

Common Pests

• Thrips and Aphids: These pests are common and can cause significant damage. Implement a preventative spray program during the flowering phase and use insecticidal soaps or chemical treatments as necessary.
• Larger Pests: Porcupines, wild pigs, and birds can also pose a threat. Use physical barriers or deterrents to protect the plants.

Diseases

• Rots: Arum lilies are susceptible to various rots, including crown rot, root rot, and pythium rot. Ensure well-drained soil and avoid overwatering to prevent these diseases.
• Fungal Infections: Regularly remove dead and decaying debris around the plants to reduce the risk of fungal infections such as powdery mildew, gray mold, and blight.

Weed Control

Effective weed control starts with proper soil preparation. Use registered pre-sprouting herbicides before planting to manage weed seeds in the soil. Always follow herbicide label instructions to prevent contamination. Manual weeding and mulching can help keep the planting area weed-free, reducing competition for nutrients and water.

Conclusion

Propagating and caring for Calla and Arum lilies requires attention to detail and adherence to best practices in soil preparation, planting, and maintenance. By following the detailed guidelines on soil preparation, planting, environmental conditions, and maintenance, you can ensure the successful growth and propagation of these beautiful plants. With proper care, your Calla and Arum lilies will thrive, providing continuous blooms and enhancing your garden’s aesthetic appeal.