African blue basil

African blue basil
Hybrid parentage	Ocimum kilimandscharicum × Ocimum basilicum
Cultivar	'Dark Opal'
Origin	Peter Borchard, Companion Plants, Athens, Ohio, 1983

African blue basil (Ocimum kilimandscharicum × basilicum 'Dark Opal') is one of a few types of basil that are perennial. 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, inherited 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.

All parts of the flower, leaves and stems are edible; although some might find the camphor scent too strong for use in the kitchen, the herb reportedly yields a tasty pesto with a "rich, mellow flavor" and can be used as a seasoning in soups and salads, particularly those featuring tomato, green beans, chicken, etc.

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. Based on other purple basils, the color is from anthocyanins, especially cyanidin-3-(di-p-coumarylglucoside)-5-glucoside, but also other cyanidin-based and peonidin-based compounds.

It blooms profusely like an annual, but being sterile can never go to seed. It is also taller than many basil cultivars. These blooms are very good at attracting bees and other pollinators.

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Wikipedia