The last two summers my Calla Lilies have grown so well and so tall that they could not support their own foliage. They did bloom well, but not as well as previous years when the plants did not grow so tall. I live in southeast Missouri, about 120 miles south of St. Louis.
Certified GKH Gardening Expert
This is typically an indication that the plants are not getting enough sun. I would see if it is possible to get them just a bit more light, perhaps by thinning any plants that may be shading the area.