Answer: Zantedeschia can be top heavy when in full bloom and sometimes need to be staked. I'd drive a plant stake into the ground near the plant and then gently ease it up and tie it to the stake. When the flowers are spent they turn brown so I'd cut them off the plants. Yellowing leaves are normal with your plants. Most Calla Lilies need a rest period after flowering, so gradually withhold water until the leaves die back and let plants rest for 2 to 3 months before resuming watering to encourage new growth. Best wishes with your calla lilies!
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