Zantedeschia aethiopica aka Calla Lily

Zantedeschia aethiopica is the calla lily, also called arum lily. It belongs to Araceae, rather than the true lily family. Its native range includes South Africa and Lesotho. In the wild, it grows beside streams and ponds. It also grows in marshes, where the soil stays wet. This perennial forms upright clumps from thick underground rhizomes. It grows at a moderate rate.

Garden plants reach about 2–3 feet [0.6–0.9 metres] tall. RHS gives a broader height range of 1.6–3.3 feet [0.5–1 metre]. Its listed spread is 0.3–1.6 feet [0.1–0.5 metres]. Glossy, dark green leaves rise straight from the rhizome. They have thick stalks, fleshy blades, and wavy edges. Their shape ranges from a heart to an arrowhead. Leaves can reach 1.3 feet [0.4 metres] in length. They stay green where rain and mild weather persist. Cold or a long dry spell can cause leaf loss.

The white display consists of a spathe around a yellow spadix. The spathe forms a funnel with a pointed tip. It can reach 0.8 feet [0.25 metres] in length. Leafless stalks hold these blooms above the green leaves. The flowers have a faint scent and suit cutting gardens. North Carolina reports blooms in June and July. Chicago lists a wider season, from January through August. Bees and beetles pollinate the flowers. Round yellow-orange berries follow in clusters, and birds spread them.

Grow this plant in rich soil that holds moisture. It accepts full sun or part shade. Sun gives better flowering, while shade helps prevent scorch in hot climates. Clay and loam suit it across a broad pH range. It can grow beside ponds or in containers and borders. It also suits rain gardens and indoor growing. As a pond marginal, it tolerates water 1 foot [0.3 metres] deep. Sources list USDA zones 8–10 and UK rating H4. Protected plants may survive in USDA zone 7. Divide clumps in spring, and remove leaves that frost blackens.

Aphids, thrips, and Japanese beetles can damage this plant. Fungal and bacterial rots can attack it, including its rhizomes. A virus may also cause trouble. It can become weedy in some wet habitats. Eating it can harm people, dogs, cats, and horses. Calcium oxalate crystals cause mouth pain, swelling, and trouble swallowing. Contact can irritate the skin or eyes. PFAF lists cooked young leaves as edible but urges caution. That limited food use does not remove the documented toxicity risk.