This plant is Beeweed, also known as Bee Plant, and Cleome. Locally, there are two kinds, one yellow and one purple. They grow very quickly, especially in disturbed soil. That makes them perfect for controlling erosion after a forest fire has burned away the vegetation. We noticed entire fields of this "weed", and discovered that it is harvested to mix with the flame retardant chemicals that planes drop on forest fires. The flame retardants help stop the fire, and the seeds provide a quick source of erosion control, as well as providing food and shelter for many animals. As an added benefit, you get the beauty of entire fields of these beautiful flowers.