QuestionsHow to growFlowersSummer colour from seedSunflower 0 Vote Up Vote Down Eilish O Connor asked 14 years ago Sunflowers – have sunflowers in a pot and they were flowering but now have closed up. Can you tell me why they might have closed and what to do with them? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 7 years ago Sunflowers are annual plants that set seed and then die.The plants have set the flowers and have closed to try to develop the seeds.