It's generous to share garden plants with friends, though I don't think the seedpods will do you much good. Like most bulbs, calla lilies are best propagated vegetatively through their underground structure. I've never had anything develop from seedpods on my calla lilies, but that's not to say they haven't sprouted in your garden. Callas spread easily by their underground stems, and that's the best way to increase these plants. Divide rhizomes in late summer or early fall after digging them up for overwintering, or in spring before you set them in the ground.