Hierochloe odorata (Sweet Grass) is one of the best fragrances you can com upon in a wet prairie. Someone should turn this delicate sweet vanilla smell into a fragrance, it is really something special.
"Sweetgrass was and still is used ceremonially through burning the dried and braided grass stems for an incense or smudge. The fragrant smoke is used for purification and to carry prayers to the Great Spirit." USDA
It's typically found in wet prairies riparian areas, and wetlands. It can be used to cultivate this sweet smelling grass, however when it is planted in smaller landscapes it can spread aggressively though it's roots, I know from personal experience.
Frequently Asked Questions
Photos By: By Krzysztof Ziarnek (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/2.5-2.0-1.0)], via Wikimedia Commons