Well, many herbs, like rosemary, thyme, and the like that are evergreen-like are desert shrubs and require a rocky dry soil and lots of sun – not the rich loamy soil other vegies are begging for. Then there are things like parsley and basil, which like a rich soil, but will also eventually flower and die, since they are annuals (some parsley is biennial in warmer zones). Mint likes moist shade but also good air-flow – place it under taller trees and it will be quite happy. Just remember that herbs are more like perennial flowers than vegies – the soil needs vary more than the annual vegies do and they are not as adapted for generic gardening conditions like vegies either.