The arum lily or Zantedeschia aethiopica, commonly called the calla lily, is a large decorative flowering plant that is a perennial in mild or hot climates. It is sometimes referenced by the scientific name Calla aethiopica. Despite its misleading name, the arum lily is not a true lily and does not belong to the genus Arum. In addition, its common moniker belies the fact that the arum lily is a distinct species apart from the true calla lily, Calla palustris.
A key feature of Zantedeschia aethiopica is its unusually large spathe, which is a leaf-shaped structure positioned around the vertically oriented true flower of the plant. The spathe is typically white with a yellow tinge. Some cultivars feature other color combinations.
This plant prefers full sun but will do well in an area with partial mid-day shade. Some varieties of arum lily are hardy to USDA Plant Hardiness Zone 6. In the warmest climates, these plants can thrive outdoors throughout the year. For gardeners in colder areas, it is best to bring the arum lily indoors for the winter.
Arum lilies typically thrive in moist soil or marshy conditions. Some species could even do well in shallow standing water. Known as one of the larger flowering plants, arum lilies can sometimes grow to 2-4 feet (61-122 cm) tall at maturity.
The genus to which these plants belong was named in honor of an Italian botanical professor, Giovanni Zantedeschia. He is credited with the initial discovery of flowering specimens in South Africa. A few specific cultivars of this decorative plant include Aztec Gold, Bridal Blush, Lavender Petite, Apple Court, Harvest Moon, and Black Magic.
This attractive flowering plant can be toxic to humans when ingested, potentially causing inflammation of the oral regions as well as leading to acute onset of diarrhea and vomiting. The arum lily can also cause an allergic skin reaction in some sensitive individuals when any part of the plant is handled with bare hands. For this reason, experts recommend that gardeners wear gloves when tending the arum lily. This negative reaction is caused by calcium oxalate found throughout the plant.
Zantedeschia aethiopica is one of several flowering plants that are referred to as Easter lilies. Other so-called Easter lilies include Lilium longiflorum, Zephyranthes atamasco, and Lilium candidum. The arum lily has been featured in a number of famous paintings, including several works by Mexican mural artist Diego Rivera.