This is purple basil, also known as African Blue Basil, which is blooming right now. We planted it at the base of of our false sunflower plant to detract rabbits and it actually worked. I haven’t tried eating any of it. According to Wikipedia, “Although the combination of a perennial plant with the scent and flavor of sweet basil would seem to make it a very desirable culinary variety, the high camphor content can interfere with its use in cooking. It is, however, an attractive ornamental.” I don’t think we’ll see it next year though. None of our other basils have ever come back.