The most popular basil used in Pesto. Sweet basil is the most used of all basil varieties. It has a robust, aromatic, and spicy flavour that goes great with tomato-based dishes. Basil is an easy to grow herb that can be used for companion planting. Planting basil near tomato plants will help improve the flavour of tomatoes. Basil will also help attract predator insects that will prey on garden pests.