Hierochloe odorata prefers moist soil, and partial shade. It can withstand full sun in temperate climates and withstands winter excellently. Hardy in zones 4-9.
Sweetgrass spreads primarily through its roots. Two kinds of stems grow, the stout ones with flowers, and the lanky sterile stems. Sweetgrass is harvested by pulling off sterile stems. It's the sterile stems that are used for braiding and basketry. They grow 18-24 inches. One "plug" (a stem or two with a few inches of frizzly rhizome) can typically cover a square foot in a year. (It's recommended by growers that harvesting take place after this initial period.)
Wild stands of Sweetgrass are disappearing, due to "overpulling". When this biomass is removed from the sweetgrass stand, a little of the more precious trace nutrients is lost.
* NOTE: Sweetgrass Hierochloe odorata exists in wild stands in Connecticut, Maine, Massachussetts, New Hampshire, Rhode Island, and Vermont. It is classified as "endangered" in Maryland, North Carolina, and Pennsylvania. There are four other species species of sweetgrass (alpina, hirta, occidentalis, and pauciflora); they're not as strongly fragrant as odorata.