Basil is a leafy, fragrant annual with a bushy appearance. Basil also is considered one of the healthiest herbs. It's best when fresh, exuding a sweet, earthy aroma that indicates not only the promise of pleasantly pungent flavor, but an impressive list of nutrients. Vitamin K, essential for blood clotting, is one of them. Basil is rich in vitamins A and C, include iron, calcium, manganese, magnesium and potassium.