Did you ever find out? There is a native species, I. noli-tangere. It is supposed to range from Puget sound north along the coast at low to middle elevations. There is also a spur-less native called I. ecalcarata, which occurs from southern BC to Oregon.

Mr. Impatiens sent me some info on native North American species impatiens. Apparently I. capensis is a relatively new plant (in the evolutionary sense) to the continent, and displays widely varied characteristics. All three plants I posted are regional variations of Impatiens capensis.

FireVicar