I planted some calla lilies on the south side of my house--part sun, part shade--about 5-7 years ago. I thought they were annuals, and we enjoyed their many blooms. The next year, they came up again with only a layer of fallen leaves for mulch and protection. They've been spreading and coming back every year since then, even after bitter cold winters and sometimes two feet of snow here in Kansas City, MO. I feed my flower beds only once in early spring and once in late summer-early fall. I water them only when they're dry. These are growing in and around evergreen spreaders. My question is, I love them dearly but wonder how many years they can be expected to continue.
Calla Lilies Outdoors in Ground
Certified GKH Gardening Expert
Probably for quite some time. I think you may have a micro-climate on the side of your house, most like due to the house itself. The south side of the house is the warmest, and your house collects that heat, which keeps the ground there warmer than the rest of your yard. The callas are kept alive because of this.