ABOUT THE LEDUMS
Labrador tea is the Northamerican conterpart of Marsh rosemary.
Marsh rosemary has long been referred to as Ledum Palustre L.. As it has recently been discovered that Ledum Palustre L. belongs to the Rhododendron family, it's latin nomenclature has also changed to Rhododendron tomentosum Harmaja. This species actually does not occur in North America (though extends to the easternmost fringes of Asia).
Three species of the Ledum group of Rhododendron occur in North America and of these Rhododendron groenlandicum, Labrador Tea, which used to be known Ledum groenlandicum. Labrador tea has a long history of use amongst First Nations and is now used in gruit recipes as an alternative to Marsh rosemary.