African blue basil (Ocimum kilimandscharicum ×basilicum 'Dark opal') is one of the most cold-tolerant breeds of basil, leading to it being called a perennial, though in fact all basils are perennial as long as the weather is warm year-round. It is a sterile hybrid of two other breeds of basil, unable to produce seeds of its own, and is propagated by cuttings.
This particular breed of basil has a strong camphor scent, derived from Ocimum kilimandscharicum (camphor basil), its East African parent. The concentration of camphor is 22% (compared with 61% for O. kilimandscharicum). The concentration of the other major aroma compounds, linalool (55%), and 1,8-cineole (15%) is comparable to many basil cultivars.
The leaves of African blue basil start out purple when young, only growing green as the given leaf grows to its full size, and even then retaining purple veins. This breed is also taller than many basil cultivars.