Calla lilies (Zantedeschia) are prized for their elegant, trumpet-shaped blooms. While generally resilient, their vibrant flowers can turn brown. This browning can be a natural part of the plant’s life cycle, or indicate environmental stress or care issues.
Understanding Natural Browning
Browning in calla lily flowers can be a normal part of the plant’s aging process. As a bloom reaches the end of its natural lifespan, typically after several weeks, it will gradually lose color and vibrancy, often turning green before browning and shriveling. This allows the plant to redirect energy from the spent flower to developing its rhizomes for future growth. If browning occurs slowly and affects older blooms, it is usually not a concern.
Watering Issues and Solutions
Both insufficient and excessive watering can lead to calla lily flowers turning brown. Underwatering causes dehydration, resulting in crispy, dry edges on flowers and leaves. The plant may also appear wilted as it struggles to transport moisture. To prevent this, maintain consistently moist soil, especially during the active growing season. Check the top inch of soil for dryness before watering, as container plants typically need more frequent watering.
Conversely, overwatering can be equally damaging, leading to waterlogged soil that suffocates roots and causes root rot. Symptoms of overwatering include yellowing leaves, soft or mushy stems, and wilting despite the soil being wet. Flowers may turn brown as the plant struggles to absorb oxygen and nutrients. Ensure proper drainage; use well-draining potting mix for containers and amend heavy garden soil with organic matter. Always allow excess water to drain completely from pots.
Environmental Factors Affecting Flowers
Unsuitable environmental conditions, including light, temperature, and humidity, influence calla lily flowers. Calla lilies prefer bright, indirect light, though they can tolerate full sun in cooler climates or partial shade in hotter regions. Too much direct sunlight can scorch delicate flowers and leaves, causing them to brown and become crispy. If the plant receives excessive direct sun, move it to a location with dappled shade or provide afternoon shade.
Temperature extremes also impact calla lilies. They thrive in temperatures between 60 to 80 degrees Fahrenheit (15-27 degrees Celsius). Exposure to temperatures below 50 degrees Fahrenheit (10 degrees Celsius) can cause damage, while excessively high temperatures stress the plant, leading to browning. Low humidity can cause flower and leaf tips to dry out and turn brown. Misting the foliage or placing the plant on a pebble tray can help increase ambient humidity.
Other Causes of Browning
Nutrient Imbalances
Nutrient imbalances can contribute to browning. A lack of essential nutrients in the soil can hinder the plant’s ability to produce healthy blooms, leading to discoloration. For instance, potassium deficiency can result in yellow or brown leaf margins and reduced flowering. Too much nitrogen can promote lush foliage at the expense of flower production, weakening blooms. Use a balanced, slow-release fertilizer at planting or a balanced liquid fertilizer during the growing season.
Pests and Diseases
Pests and diseases can also cause browning. Common sap-sucking pests like aphids, spider mites, and thrips feed on plant tissues, leading to discoloration and wilting. Regularly inspecting plants for signs of infestation, such as sticky residue or tiny spots, allows for prompt treatment with insecticidal soap or neem oil. Fungal diseases, such as botrytis blight or brown spot, thrive in wet, humid conditions and cause brown spots or gray mold. Improve air circulation, avoid overhead watering, and remove affected plant parts.
Maintaining Healthy Calla Lily Blooms
Promoting vibrant, long-lasting calla lily blooms involves consistent and attentive care. Deadheading, the removal of spent flowers, is beneficial. Removing old flowers prevents the plant from expending energy on seed production, redirecting resources to rhizomes for stronger growth and more abundant blooms in subsequent seasons. To deadhead, clip the stem of the spent flower near its base, ensuring no bare stem is left protruding. Consistent monitoring for early signs of stress, whether from watering issues, environmental factors, or pests, allows for timely intervention, helping to keep calla lilies healthy.