There are four main types of sweet garden basil. The most common, sweet basil, has a strong taste reminiscent of cloves and used mainly in making basil pesto and as a flavoring for tomato-based Italian dishes. Genovese sweet basil is known as the tastiest sweet basil cultivar. Dwarf green basil has a similar taste to sweet basil; purple-leaved basil has a stronger aroma and flavor than sweet basil; and scented-leaf basil comes in many varieties that impart foods with the tastes of cinnamon, lemon, cinnamon and anise, which has a black licorice flavor. Less common is Thai basil, which looks like regular sweet basil but has a unique spicy taste that complements the lemongrass and other herbs and spices used in Thai cooking.
Boxwood basil is so named because of its resemblance to a boxwood shrub. Its small leaves taste very similar to regular sweet basil. Its most unique features are its height and shape. While regular sweet basil typically grows to heights between 2 and 2 1/2 feet and sprawls out as it grows, boxwood basil only grows between 12 and 16 inches tall and has a compact, bushy shape, which makes it ideal for indoor cultivation or small outdoor gardens.
Regular sweet basil has leaves between 2 and 3 inches in length, while boxwood basil has tiny leaves less than half the size. While the smaller leaves give boxwood basil a more appealing and ornamental appearance, picking them from the stems to make pesto or other dishes with basil as the main ingredient is tedious since it takes at least twice as many to attain the same volume of regular basil leaves.
Besides pesto and Italian sauces, both types of basil add interesting aromas to potpourris when dried and mixed with other ingredients. In either fresh or dried form, both basil types add unique flavors and scents to savory baked goods, teas, ice cream, honeys, jellies and vinegars.