The Alcatraz Flower, also known as the Calla Lily or Arum Lily (Zantedeschia aethiopica), is a striking plant with elegant, trumpet-shaped blooms. Though not a true lily, it’s named the “Alcatraz Flower” for its remarkable resilience and ability to thrive on Alcatraz Island despite harsh conditions. Its distinctive appearance and hardy nature make it a popular choice for gardeners.
What is the Alcatraz Flower?
The Alcatraz Flower is primarily known by its common names, Calla Lily and Arum Lily, with its botanical designation being Zantedeschia aethiopica. This species is a rhizomatous herbaceous perennial, meaning it grows from an underground stem and returns year after year. Its most distinguishing feature is the inflorescence: a large, pure white, trumpet-shaped spathe, up to 9 inches long, gracefully enfolds a prominent yellow, finger-like spadix.
The plant’s foliage is equally attractive, featuring large, glossy, dark green leaves that are typically arrow-shaped or heart-shaped, growing up to 18 inches long. While the classic Zantedeschia aethiopica is known for its white blooms, some cultivars exhibit spathes with green stripes or pinkish bases. This species is native to Southern Africa, thriving in moist environments like stream banks and marshes. The “Alcatraz Flower” name stems from its ability to flourish on Alcatraz Island, a testament to its robust growth even in challenging coastal conditions.
Growing and Caring for Alcatraz Flowers
Cultivating Alcatraz Flowers requires attention to their environmental needs. They perform well in full sun to partial shade, preferring partial shade in hotter climates to prevent scorch. Aim for a spot with at least 4-6 hours of direct sunlight daily or bright, indirect light.
Ideal soil for Zantedeschia aethiopica is rich, well-draining, and retains consistent moisture. It prefers a slightly acidic to neutral pH (6.0-7.5). Incorporating organic matter like compost improves fertility and drainage. Consistent watering is important during the active growing season, keeping the soil evenly moist without waterlogging, which can lead to rhizome rot.
Alcatraz Flowers prefer warm conditions, with optimal temperatures 60-80°F (15-27°C), and appreciate humidity. Temperatures below 50°F (10°C) can prompt dormancy. During the growing season, apply a balanced liquid fertilizer (e.g., 10-10-10 NPK) every two to six weeks to support vigorous growth and abundant flowering. Avoid over-fertilization, as this can lead to excessive foliage at the expense of blooms.
Pruning involves deadheading spent flowers by cutting the stem close to the base. This encourages more blooms and maintains a tidy appearance. Remove yellowing or damaged leaves to promote overall plant health. Alcatraz Flowers can encounter issues like rhizome rot (due to poor drainage) or pests like Japanese beetles and aphids. Proper soil conditions and regular inspection help manage these concerns.
Propagating and Overwintering
Propagating Alcatraz Flowers is straightforward, with rhizome division being the most common and effective method for home gardeners. This can be done in late summer or early fall after flowering, or in early spring before new growth. To divide, carefully dig up the clump, shake off excess soil, and separate rhizomes, ensuring each piece has at least one “eye” or bud. Allow divided rhizomes to dry and form a callus for a day or two before replanting to prevent rot. While possible, seed propagation is less common as it takes longer and may not yield true-to-parent plants.
Overwintering Alcatraz Flowers depends on the climate zone. In colder regions, generally USDA Zones 7 and below, rhizomes are sensitive to freezing and must be lifted before the first hard frost. After lifting, clean excess soil, dry for a few days, then store in a cool, dark, dry location, such as in peat moss within a vented bag, at around 60°F (15°C). In milder climates, typically USDA Zones 8-10, Zantedeschia aethiopica can remain in the ground year-round. A thick layer of mulch provides additional protection. In these areas, the plant may remain evergreen with consistent moisture and mild conditions.
Important Considerations and Uses
The Alcatraz Flower (Zantedeschia aethiopica), though beautiful, contains calcium oxalate crystals, making all parts toxic if ingested. Ingestion can cause a severe burning sensation and swelling of the mouth, tongue, and throat. Exercise caution around children and pets, and wear gloves when handling to avoid skin irritation.
Beyond ornamental appeal, the Alcatraz Flower serves various uses in gardening and floristry. It is a popular choice for borders, containers, and can be grown as a marginal plant in water gardens or along pond edges, reflecting its natural habitat. Its striking, long-lasting blooms make it a favored cut flower, frequently used in bouquets and floral arrangements for its elegant form and classic white color.