i did find a partial answer to my question at:
http://www.gruitale.com/bot_wildrosemary.htm
seems that this website states that:
"...Availability: unavailable, but it's North American counterpart
Labrador Tea is a satisfactory alternative...
...ABOUT THE LEDUMS
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 Labrador Tea (Rhododendron groenlandicum), which used to be known as 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."...