They enjoy bright, indirect light or filtered sunlight, but can get burned in direct, full sunlight. In order to get the best mandevilla flowers throughout the summer, give your mandevilla plant a high phosphorus, water soluble fertilizer once every two week. This will keep your mandevilla vine blooming wonderfully.
Grow outside all summer long and bring in to the indoors in the fall for continual blooms. A trellis is needed for optimum growth habit.