Many herbs are really great companions to other plants growing in the garden.
Lots of herbs have strong scents that can be used to confuse pests that will identify their targets through smell.
Planting rosemary near your cabbage is a good way to deter the white cabbage butterfly. Right now I have my rosemary plant all by herself in the herb garden. hmmm
Borage is a good companion planted w/ tomato, squash, strawberries. It's one of the best bee attracting plants. Borage adds trace minerals to the soil and is a good addition to the compost pile. I have planted some this year and hope to find out if it really is a benefit to most any plant growing next to it by increasing resistance to pests and plant diseases.
Chives is known to improve the growth of carrots & tomato. And a good bug deterent for roses & fruit trees. The scent of chives will deter many pests. Planted among apple trees, it helps prevent scab but apparently only after about three years of planting.
