The tallest of the callas, Z. aethiopica, is particularly suited to this environment as it can be placed in up to ten inches of water. In some colder areas of the US, this is below the level of ice in the winter and here it can stay. However, it is always safest to overwinter inside or experiment with one outside/one inside if you have any doubts as to hardiness.
Boggy, wet situations can encourage bacterial disease, so keep an eye on your plants growing in pond margins and remove if disease begins to rot foliage or flowers where they meet the soil.
In pots on the deck, think about plunging pots in with other exotic tropicals and sub-tropicals that love moisture such as colocasia and canna. As the summer wears on and their companions begin to outpace them, you can remove the callas, start to withhold moisture and begin their period of dormancy.
A little bit of work for a whole lot of elegance
Because the soft, half cones of calla are a mainstay of upscale florists and still regarded as an exotic bloom, they lend a touch of sophistication to a garden or a potted container arrangement. Once you’ve mastered matching this plant with the correct growing conditions, you’ll be thrilled by the oohsand ahhs you receive.
You don’t need to let on how easy they were to grow.