They are popular houseplants and need to be kept away from any pets, as they are poisonous. Wear gloves to prevent the Nephthytis sap from irritating your skin, if you have sensitive skin. They are popular for their arrow-shaped, variegated leaves, these perennial plants are native to tropical America and are commonly grown as indoor houseplants. Slow growing and climbing, Nephthytis plants will last a long time in a container. In fact, Arrowhead Plants are extremely hardy and can even survive mistreatment.