I live in SW OK and am unable to get calla lillies to re-bloom either in pots or in ground. Have tried north, east and south side of home. The west side is full sun. Caladiums grow very well for me and I have tried the exact same treatment for both. When planting in early May both ground or in pot, I use Osmocote and Miracle Grow Potting Soil. I water twice a week until frost. Each month they get a dose of Miracle Grow granules, 1 heaping tablespoon to a gallon of water. Any suggestions?