Understanding the Bloom Cycle of Arum Lilies and Calla Lilies

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Arum lilies (Zantedeschia aethiopica) and Calla lilies (Zantedeschia spp.) are renowned for their elegant, trumpet-shaped blooms and lush, green foliage. Understanding their bloom cycle is essential for gardeners who want to enjoy these stunning flowers at their best. This comprehensive guide will delve into the various stages of the bloom cycle for Arum and Calla lilies, incorporating insights from expert sources to provide you with a detailed understanding of how to care for these plants throughout the year.

Bloom Cycle Overview

Natural Habitat and Blooming Season

Arum and Calla lilies originate from South Africa, where they grow in marshy areas. This natural habitat influences their bloom cycle, which typically begins in late spring and continues through the summer. However, the exact timing can vary based on geographic location and specific variety.

  • Bloom Period: Late spring to summer, with peak blooming occurring from late spring to early summer.
  • Influencing Factors: Temperature, light, and water availability significantly impact the bloom cycle.

Stages of the Bloom Cycle

1. Dormancy

  • Timing: Typically during the winter months.
  • Characteristics: During dormancy, the plants rest and conserve energy. This stage is crucial for the health and vigor of the lilies in the upcoming growing season.
  • Care: Minimal watering is required. Ensure the bulbs are kept in a cool, dry place if stored indoors.

2. Emergence

  • Timing: Early spring.
  • Characteristics: As temperatures rise, the bulbs begin to sprout, sending up new shoots. This marks the beginning of the active growth phase.
  • Care: Gradually increase watering to support new growth. Ensure the soil is well-drained and rich in organic matter.

3. Vegetative Growth

  • Timing: Mid to late spring.
  • Characteristics: Leaves and stems grow rapidly during this stage, forming the lush green foliage that will support the blooms.
  • Care: Regular watering and fertilization are essential. Use a balanced fertilizer to promote healthy foliage development.

4. Bud Formation

  • Timing: Late spring.
  • Characteristics: Flower buds begin to form as the plant redirects its energy from foliage growth to flower production.
  • Care: Continue with regular watering and switch to a high-phosphorus fertilizer to support bud development.

5. Blooming

  • Timing: Late spring to early summer.
  • Characteristics: The flowers open, displaying their full beauty. Each bloom can last several weeks, depending on the variety and growing conditions.
  • Care: Maintain consistent watering. Deadhead spent blooms to encourage further flowering and prevent the plant from putting energy into seed production.

6. Post-Bloom

  • Timing: Mid to late summer.
  • Characteristics: After the blooming period, the plants begin to prepare for dormancy. Foliage may start to yellow and die back.
  • Care: Gradually reduce watering. Allow the foliage to die back naturally, as it helps nourish the bulbs for the next growing season.

Indoor and Outdoor Growing Tips

Indoor Care

  • Light: Provide bright, indirect light. A south-facing window is ideal.
  • Temperature: Maintain a consistent temperature between 18°C to 24°C (65°F to 75°F).
  • Humidity: Keep the humidity levels moderate. Mist the plants occasionally if the indoor air is dry.

Outdoor Care

  • Planting Location: Choose a location with partial shade to full sun. Ensure the soil is well-drained and enriched with organic matter.
  • Watering: Keep the soil consistently moist but not waterlogged. Water more frequently during hot, dry periods.
  • Mulching: Apply mulch around the base of the plants to retain moisture and regulate soil temperature.

Common Problems and Solutions

Pests and Diseases

  • Aphids and Thrips: These pests can damage the foliage and flowers. Use insecticidal soap or neem oil to control infestations.
  • Bacterial Soft Rot: Prevent this disease by ensuring good air circulation and avoiding overhead watering. Remove and destroy affected plants immediately to prevent the spread.

Environmental Stress

  • Overwatering: Can lead to root rot. Ensure the soil is well-drained and do not allow the bulbs to sit in water.
  • Underwatering: Can cause the plants to wilt and the blooms to fade prematurely. Maintain consistent moisture levels in the soil.


Understanding the bloom cycle of Arum and Calla lilies is crucial for ensuring their health and vibrancy. By following the detailed care instructions for each stage of the bloom cycle, gardeners can enjoy the stunning beauty of these lilies year after year. Proper care, including adequate watering, fertilization, and pest management, will result in healthy plants and abundant blooms, enhancing the aesthetic appeal of any garden or indoor space.

By adhering to these guidelines, you can ensure that your Arum and Calla lilies thrive, providing spectacular blooms and lush foliage throughout the growing season.

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