.
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.
ANOTHER SOLUTION is THIS :
The perimeter is 4 + 3 + 4 + 3 = 14 ft.
Planting the flowers along the perimeter at 1 ft apart, you will plant 14 flowers.