Water the flowers with hot water because the water temperature is too hot, which makes the cells of the flowers lose their activity.

Since water is still used for watering flowers with cold water, the cells of flowers whose temperature must be higher than zero can generally remain active in water above zero.

Generally speaking, cold water will inactivate cells. When the temperature changes to a temperature that cells can adapt to, cells can recover their activity, while hot water will completely destroy the cell structure, and even if the temperature decreases, cell activity will not recover.