While herbs add zing to our cooking and help battle illness, they are also of great value to wildlife, as well as a natural method of pest control. Many flowers and vegetables benefit from growing close to herbs such as sage, thyme, oregano, garlic, and chives. The herbs act as companion plants and actually repel certain pests away from the plants you want to grow. Some other herbs literally drive insects off, and some contain chemicals that inhibit insect growth or actually kill certain pests. Companion planting is recommended by organic gardeners as a means of improving plant performance without chemical fertilizer and pesticides.
Herbs play an important role in the life cycle of butterflies.
The key to attracting butterflies is providing them with the specific plants on which they lay their eggs. If you want butterflies, you are going to have to tolerate the presence of caterpillars. Most do minimal damage. In my experience, the brightly striped caterpillars have never eaten more than their share, but it doesn't hurt to plant enough for both you and them. Since native butterfly species are adapted to the flora of their range, many choose to lay their eggs on one or two specific plants.