5 + 5 = 10 flowers along the two longer edges PLUS 2 + 2 = 4 flowers along the two shorter edges ( ! the corners are just occupied !). In all, 10 + 4 = 14 flowers.
The perimeter is 4 + 3 + 4 + 3 = 14 ft. Planting the flowers along the perimeter at 1 ft apart, you will plant 14 flowers.