Caladiums should never get direct sun. They need very bright light, though. They also like fertile soil.
Try to plant in a location that enjoys dappled sun and remember to water moderately. Keep in mind when planting that Red flash is thought of as tender, so remember to wait until your soil is warm and the night time temperature is well above freezing before moving outside.When grown in the ground caladiums should be dug and stored each year before frost.1
Ensure that temperatures are mild and all chance of frost has passed before planting out, as Red flash is a tender plant.Flash rouge, Angel wings
1 http://www.plantsrescue.com/tag/caladium-x-hortulanum/