If only it did not like such regular watering, the common white calla, Zantedeschia aethiopica, would be quite a sustainable perennial. Once established, it can be difficult to get rid of, particularly in well watered gardens. Even unwatered plants that die to the ground through dry summer weather are merely dormant and waiting for rain to regenerate and bloom.
The remarkably elegant blooms stand about two or three feet tall, each with a single spathe loosely wrapped as a flaring cone around a spadix that supports the indistinguishable diminutive flowers. The bright white spathe is often more than four inches wide, and can be twice as wide in shade. The spadix is only about three or four inches long, and as yellow as Big Bird. The spongy dark green leaves are about a foot or two tall.
‘Green Goddess’ blooms with a longer and recurved spathe with a green tip and margins. Colorful callas are actually different specie. All parts of all types of callas are incidentally toxic.