Find your local farmers market!
Lemongrass is a very commonly-used herb in Asian cuisine with a mild citrus flavor. This plant has been used since ancient times as a medicinal and culinary herb as well as a traditional pesticide and preservative! This grass can be prepared as either a dried leaf as well as powdered, but some recipes even call for it fresh. Adding it to Asian-inspired Paleo dishes is a great idea for increasing the authentic flavor; I have noticed that many Thai dishes in particular are very close to Paleo, requiring little or no modification, and lemongrass is often a feature flavor. In fact, my favorite recipe that includes lemongrass is my Thai Green Curry!
Fresh lemongrass is available on Amazon!