Plant Information on Poisonous Elephant Ears

Elephant ear, Colocasia esculenta, bears distinctive, tropical-looking foliage that many use for a houseplant, container plants or landscaping accents. As common as a garden plant in many places removed from the tropics, elephant ear carries with it a double-edged sword: it's beautiful to look at but it also proves highly toxic when consumed by humans or animals.

In general, elephant ear grows anywhere from two to five feet in height and produces large, irregular, oval-shaped leaves on long stalks that resemble its namesake. However, a wide selection of varieties offer a laudable range of colorful foliage. For example, "Black Magic" has burgundy-black foliage, while "Lime Zinger bears electric chartreuse green foliage. "Nancy's Revenge" mixes things up with creamy white centers laid in dark green leaves. Along with its colorful foliage, the elephant ear also sprouts greenish to yellow flowers.

As a native of the tropics, elephant ear grows as a perennial tender or hardy bulb. It grows from large, brown tubers. A shade-loving plant, it thrives in areas with partial sun, but it can grow in full sun as long as its soil stays moist. In addition to the garden or landscape, it makes a great houseplant.

Elephant ear grows best when planted in moist soil with periodic applications of fertilizer, either a slow-release or water-soluble variety. When growing in colder zones, dig up the bulb in the fall and replant it the following spring to ensure its continued success, as freezing conditions will kill elephant ear. Wait until first frost to dig up the bulb and cut the stalks to four inches from the ground. Once the plant is dug, let dry for a day before storing in a cool area.

Although the presence of elephant ears can bring a hint of the tropics to even the most mundane landscape, the entire plant of Colocasia esculenta is poisonous when digested, unless cooked first, according to North Carolina State University. The presence of calcium oxalate crystals provides the toxic element in this plant.

Symptoms of ingested elephant ear, according to the National Institutes of Health, include diarrhea, nausea and vomiting, as well as redness and burning of the eyes. When eaten, the plant causes severe pain in addition to burning and swelling of the mouth, tongue, throat and eyes. While not inherently fatal, swelling can become severe enough to block airways. If consumed, use a cold, wet cloth to wipe out the mouth and any residual plant sap in the eyes or on the skin.