Overview
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy, commonly known as the white arum lily, is a striking herbaceous perennial plant native to South Africa. It is grown for its beautiful flowers and attractive foliage, and is popular in gardens and as a cut flower.
Common names
The white arum lily is also known by several other common names, including the white calla lily, trumpet lily, or arum lily. In South Africa, it is sometimes known as the "Pig's ear" or "Kaffir lily", although these names are considered inappropriate due to their derogatory connotations.
Appearance
The white arum lily produces a single flower stalk that can reach up to 3 feet tall. The flowers are pure white and trumpet-shaped, with a yellow spike or spadix protruding from the center. The leaves are large and leathery, typically green with white or silver markings. As the plant matures, it develops a thick rhizome that produces additional shoots and flowers.
Uses
White arum lilies are commonly used as cut flowers for arrangements and bouquets due to their elegant appearance and long vase life. In gardens, they are often planted in moist, shaded areas as accent plants and can be grown as houseplants. In addition to their ornamental value, arum lilies are also used in traditional African medicine for their purported analgesic, anti-inflammatory, and antifungal properties.
Light Requirements
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy grows best in bright, indirect sunlight. It can tolerate some direct sunlight but should be protected from strong afternoon sun. If grown indoors, it should be placed near a south-facing window or under grow lights that provide full-spectrum lighting.
Temperature Requirements
This plant prefers warm temperatures between 65-75°F (18-24°C). It can tolerate temperatures as low as 50°F (10°C) but should be protected from frost. In colder climates, it is best grown indoors or in a greenhouse.
Soil Requirements
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy thrives in well-draining soil that is rich in organic matter. A mix of peat moss, perlite, and vermiculite works well. The pH should be between 5.5-6.5. Avoid using heavy, clay soils that retain moisture, as this can cause root rot.
Cultivation Methods
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy grows best in warm and humid conditions. It thrives in loamy soil that is rich in organic matter and well-drained, with a pH between 5.5-7.0. They prefer partial shade and should be sheltered from strong winds to prevent damage to the leaves and flowers. Plant the rhizomes about 7-10cm deep and 20-25cm apart.
Watering Needs
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy requires regular watering to keep the soil consistently moist but not waterlogged. Water the plants every three days in the growing season and reduce the frequency during the dormant period. Avoid wetting the leaves and flowers to prevent fungal diseases.
Fertilization
The plant requires regular fertilization to encourage growth, flowering, and prevent nutrient deficiencies. Fertilize with a balanced 10-10-10 NPK fertilizer every two weeks during the growing season. Reduce the application rate during the dormant period to prevent excessive growth.
Pruning
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy does not need much pruning, but removing spent flowers and yellowing leaves will promote healthy growth and prevent fungal disease. Cut the spent flowers and leaves down to the base of the plant. Do not remove green leaves as they are essential for photosynthesis and plant growth.
Propagation of Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy
Zantedeschia melanoleuca (Hook.f.) Engl. var. concolor Burtt Davy, commonly known as Calla Lily, can be propagated by using different methods, including division, seed, and tissue culture.
Division
Division is the most common method used to propagate Zantedeschia melanoleuca. It involves separating the plant's rhizomes and replanting the sections into individual pots or directly into the garden. The best time to divide Calla lilies is in the spring, just as new growth appears. Before dividing, the rhizomes are carefully removed from the soil and separated using a sharp, clean knife. Each section should have at least one healthy shoot and root. The divided rhizomes should then be planted at the same depth as they were before and watered thoroughly.
Seed
Propagation by seed is also possible but is less popular, mainly because the process is slow, and seed-grown plants may vary greatly from their parent plants. The seeds should be sown in a well-draining potting mix and kept moist in a warm, humid environment until they germinate. The seedlings can be transplanted when they are big enough to handle. It is essential to note that seed-grown Zantedeschia melanoleuca may not flower for up to two years after germination.
Tissue culture
Tissue culture is a technique used by more experienced gardeners or nurseries to propagate Calla lilies. This method involves taking tiny pieces of the plant's tissue and placing them in nutrient-rich agar mediums to produce new clones. Tissue culture not only allows for a more precise reproduction of desirable cultivars but also enables the quick mass production of plants under sterile conditions.
Disease Management
There are a few common diseases that may affect Zantedeschia melanoleuca var. concolor. Some of the diseases and their management techniques are:
- Root Rot: This disease is caused by the fungus Pythium spp. and can be noticed by the wilting and yellowing of the leaves, eventually leading to plant death. To prevent the occurrence of root rot, ensure that the plant's soil is well-drained and do not overwater the plant. Remove any visibly affected plant parts and treat healthy roots with a fungicide.
- Leaf Spot: This disease is caused by the fungi Cercospora spp. and can be recognized by the occurrence of brown, water-soaked lesions on the leaves. It can be prevented by avoiding overhead watering and handling plants with care. In case of an outbreak, remove affected leaves and treat with a fungicide.
- Mosaic Virus: This viral disease is characterized by yellowing and puckering of the leaves, growth stunting, and distorted flowers. The virus is spread through infected plant material, so ensure that any new plants are free from the virus. Otherwise, the infected plant should be removed and destroyed to prevent the spread of the virus.
Pest Management
There are several pests that can infest Zantedeschia melanoleuca var. concolor. Some of the common pests and their management methods are:
- Spider Mites: These pests are tiny and are often found on the underside of leaves. They can cause stippling of the leaves and reduced plant growth. They can be controlled by spraying the plant with a blast of water or treated with insecticidal soap.
- Thrips: These pests are tiny and feed on the leaves and flowers, causing discoloration and deformation. They can be controlled by removing any infected plant material and using sticky traps.
- Slugs and Snails: These pests can damage the plant's leaves, especially during the night. They can be controlled by handpicking them and placing a layer of copper tape around the base of the plant.
