How to care for your Large Green Calla Lilies: Upon receiving your large calla lilies, inspect all flowers, take them out of the box and remove all packaging. They may appear limp or tired after their journey and this is completely normal. Large calla lilies require at least 6 hours in water to re-hydrate after their trip and blooms will open in approximately 1-3 days. Hold the ends of the stems underwater and trim them diagonally at least ¼ inch from the ends using a sharp knife. Place your calla lilies immediately in clean vases or containers with lots of fresh water. Keep the flowers in a cool, dim location, away from direct sunlight, draughts or excessive heat. To maximize vase life, re-cut the stems and change the water in the vases every day using the above steps. TIP: Large calla lilies have a natural bend to their stems. In order to minimize the curve, lay the flowers horizontally on a flat surface and wrap the ends of the stems in wet newspaper. Allow them to remain for up to 4 hours, checking on them from time to time.