The Pink Arum Lily (Zantedeschia rehmannii) is a beautiful ornamental plant, admired for its distinctive pink, funnel-shaped spathe and elegant form. This striking plant enhances various garden settings and is a popular choice for cut flower arrangements.
Understanding the Pink Arum Lily
The Pink Arum Lily, scientifically known as Zantedeschia rehmannii, is not a true lily; it belongs to the Araceae family. This herbaceous perennial is characterized by its distinctive pink, funnel-shaped spathe, often mistaken for the flower. The actual tiny flowers are found on the central yellow spike called the spadix.
The leaves of Zantedeschia rehmannii are typically lance-shaped and lush green, sometimes featuring subtle white spots. Originating from the grasslands and rocky hillsides of eastern South Africa and Swaziland, this plant thrives in subtropical climates. It is a tuberous geophyte, growing from an underground tuber, and undergoes a dormancy period during cooler months.
Essential Care for Pink Arum Lilies
Caring for Pink Arum Lilies requires understanding their specific environmental needs for robust growth and prolific flowering. Providing the right conditions for light, soil, water, temperature, nutrients, and proper planting techniques is fundamental.
Light Needs
Pink Arum Lilies flourish in full sun to partial shade. While they appreciate ample light for optimal flowering, intense, direct afternoon sun, especially in hotter climates, can scorch their leaves. A position offering bright, indirect light for at least six to eight hours daily is ideal. If grown indoors, place them near a bright window that avoids direct, harsh sunlight.
Soil Requirements
These plants prefer well-draining soil that remains consistently moist but never waterlogged. An ideal soil mix is loamy and rich in organic matter, supporting nutrient needs and healthy root development. A slightly acidic to neutral pH, around 6.5, is generally suitable. When planting in containers, ensure good drainage with a pot that has drainage holes.
Watering Practices
Consistent moisture is important for Pink Arum Lilies, especially during their active growing season from spring through summer. Watering every 2-3 days may be necessary in high temperatures or dry environments. Avoid overwatering, which can lead to rhizome rot. Allowing the top inch of soil to dry slightly between waterings helps prevent root issues. Reduce watering significantly during dormancy in autumn and winter.
Temperature and Humidity
Pink Arum Lilies prefer temperate to warm climates, with optimal temperatures ranging between 18°C and 25°C (64°F and 77°F). Temperatures should not drop below 5°C (41°F) to protect their rhizomes. They also appreciate moderate to high humidity, around 60%. In dry indoor environments, increasing humidity can benefit the plant.
Fertilizing
During the active growing season, from spring to early fall, Pink Arum Lilies benefit from regular fertilization. A balanced liquid fertilizer, such as a 10-10-10 formulation, applied every four to six weeks, provides essential nutrients. A fertilizer with slightly higher phosphorus content can encourage robust flowering. Fertilizing every two weeks during the flowering period can help prolong and enrich the blooms.
Planting Considerations
The best time to plant Pink Arum Lily rhizomes is in spring, after the last frost. For outdoor planting, rhizomes should be placed approximately 8 cm (3 inches) deep and spaced about 40-45 cm (16-18 inches) apart. When planting in containers, use a pot only slightly larger than the rhizome, covering it with about 2.5 cm (1 inch) of soil. The shoot buds of the rhizome should face upwards.
Common Challenges and Solutions
Pink Arum Lilies can encounter certain issues that affect their health and appearance. Recognizing these common problems and applying appropriate solutions helps maintain the plant’s vitality.
Yellowing leaves often signal improper watering (too much or too little) or a nutrient deficiency. Ensuring the soil is consistently moist but not waterlogged can resolve most cases. If nutrient deficiency is suspected, applying a balanced fertilizer can help.
A lack of blooms can be attributed to insufficient light, incorrect fertilization, or issues with dormancy. Providing adequate bright, indirect light and using a high-phosphorus fertilizer during the growing season can encourage flowering. Ensuring the plant undergoes a proper dormancy period with reduced watering and cooler temperatures can also trigger re-blooming.
Pink Arum Lilies may also be susceptible to pests such as aphids and spider mites, and diseases like root rot. Root rot typically results from overwatering or poorly draining soil, so improving drainage and adjusting watering frequency are important preventative measures. Regularly inspecting the undersides of leaves can help detect pests early, which can often be managed by hand-squashing or using appropriate horticultural treatments.
Propagating Pink Arum Lilies
Propagating Pink Arum Lilies is primarily achieved through the division of their rhizomes. This method is most effective when the plant is dormant, typically in late autumn or early spring before new growth begins.
To propagate, carefully dig up the plant and gently shake off excess soil to expose the rhizomes. The larger rhizome can be cut into several sections, ensuring each piece has at least one visible “eye” or bud, where new growth will emerge. These divided sections can then be replanted in well-draining soil, either in pots or directly in the garden, at the appropriate depth and spacing. New plants will sprout from these divisions.
Important Safety Information
All parts of the Pink Arum Lily (Zantedeschia rehmannii) contain calcium oxalate crystals, which can cause irritation. These needle-shaped crystals can lead to discomfort if the plant material is ingested or comes into contact with skin or eyes.
Symptoms of exposure can include localized pain, swelling, and irritation of the mouth, throat, or skin. Exercise caution, especially around children and pets. Wearing gloves when handling Pink Arum Lilies can help prevent skin irritation. If ingestion occurs, rinse the mouth and offer a cool drink, but seek medical attention if swelling or breathing difficulties arise.