According to Fernald, Rosa johannensis is found in the calcareous area, R. blanda in the acid or barely calcareous coastwise region.

Rhodora, 20(233): 90-96 (May 1918)
ROSA BLANDA AND ITS ALLIES OF NORTHERN MAINE AND ADJACENT CANADA.
M. L. FERNALD

In the genus Rosa this segregation along lithological lines is as pronounced as in other genera, with the result that in the acid or hardly calcareous coastwise region from southern New England to northeastern New Brunswick, the Magdalen Islands and southern Newfoundland Rosa virginiana L. and R. carolina L.1 (R. humilis Marsh.) abound in the drier habitats and R. nitida Willd. in the bogs; while swamps and pond-shores northward to Megantic Co., Quebec, north-central Maine, and southwestern New Brunswick are often characterized by the abundance of R. palustris Marsh. (R. carolina Auth., see foot-note 1). In these four species of southern arid habitats the infrastipular prickles are normally present, the pedicels, hypanthiums and hips more or less bristly, and the achenes are borne at the base of the hip.

In the calcareous area to the north and northwest, however, from the St. John valley in Maine to Gaspé and Anticosti, these species are practically unknown (with the exception of rare colonies of R. nitida in sphagnous bogs and local colonies of R. palustris in the Devonian sandstones about Gaspé Bay) and their places are taken by three species of quite different character; without infrastipular prickles, with glabrous pedicels, hypanthiums and hips, and with the achenes borne on the inner walls as well as at the base of the hips. These three northern calcicolous shrubs have all passed as R. blanda Ait., and since there is some question as to the exact identity of R. blanda it is necessary first to consider the original description of that species.

This rose is threatened/endangered, so it would be excellent if those who have suitable conditions would grow it.

See list of threatened/endangered native US roses here: http://plants.usda.gov/java/threat?txtparm=rosa&category=sciname&familycategory=all&duration=all&growthhabit=all&wetland=all&statefed=all&sort=sciname&submit.x=61&submit.y=6].

listed as diploid in 'Resistance Breeding For Powdery Mildew and Black Spot in Roses'.