Despite sharing a common name, the Peace Lily and the Calla Lily are botanically distinct plants from different families and genera. The Peace Lily, scientifically known as Spathiphyllum, belongs to the Araceae family, which includes plants like philodendrons and pothos. It is a tropical evergreen perennial native to the rainforests of Central and South America. In contrast, the Calla Lily is known as Zantedeschia aethiopica and is a member of the Araceae family. It is native to southern Africa in regions like South Africa, Lesotho, and Swaziland. This fundamental difference in origin is the primary reason for their divergent care requirements.
The most noticeable difference lies in their appearance. The "flower" of the Peace Lily is not a true flower but a specialized leaf bract called a spathe. This white, hood-like spathe surrounds a central spike, the spadix, which is covered in the plant's tiny, true flowers. Its foliage consists of broad, glossy, lance-shaped leaves that grow directly from the soil. The Calla Lily also features a spathe and spadix structure, but its spathe is typically trumpet or funnel-shaped and comes in a wider variety of colors including white, yellow, pink, purple, and black. Its leaves are also glossy but are arrowhead-shaped and often feature white or translucent speckles.
Their care needs diverge significantly due to their separate evolutionary paths. The Peace Lily is a shade-tolerant plant that thrives in bright, indirect light but will suffer in direct sun. It demands consistently moist soil and is notoriously dramatic, wilting to signal the need for water before perking up quickly after a drink. It enjoys high humidity and warm temperatures year-round. Conversely, the Calla Lily prefers much brighter light, tolerating some direct morning sun. Its watering needs are more specific; during its growth and blooming period, it likes moist soil, but it requires a dry period after flowering. Many varieties are not frost-hardy and are treated as annuals or their rhizomes are lifted in colder climates, unlike the perpetually growing Peace Lily.
Both plants are toxic and share a common defense mechanism: insoluble calcium oxalate crystals. If any part of either plant is chewed or ingested, these needle-like crystals can penetrate soft tissues in the mouth, tongue, and throat, causing immediate pain, oral irritation, excessive drooling, difficulty swallowing, and vomiting. The Peace Lily contains these crystals and additional compounds that may cause more severe gastrointestinal distress. It is often incorrectly labeled as highly dangerous, but it is generally less toxic than true lilies (Lilium spp.), which can cause acute kidney failure in cats. The Calla Lily contains the same irritating oxalate crystals but is also considered minimally to moderately toxic. For both plants, the primary concern is the intense discomfort and localized reaction, and it is advisable to keep them out of reach of curious pets and children.
