This small shrub is mostly found in or near the central and southern Appalachians; there are also scattered disjunct midwestern localities in s. Mo., n. & s. Ill., n. & s. Ind. (including Washington & Scott Cos. in the western Knobs region). Although known from about 13 states, the species is considered threatened, endangered or locally extinct in all of these except Va. (NS). It is generally associated with rocky glades or rocky riverbanks (Hill 2003d), but it can also increase in open woods after browsing or burning (J. Ceska & A. Weakley, pers. comm.). At least in northern regions, this species suffered locally from thorough eradication efforts along with B. vulgaris L. (a cultivated alien), since both species are hosts for the black stem rust of wheat (D, FNA 3, Y). In Ky. canadensis has been found at two sites on open bouldery banks of the Big South Fork (Devil's Jump and Big Shoals). There is also an old obscure report from JEFF or nearby by McMurtrie (1819), and it has been reported from CALL by Woods & Fuller (1968) but their coll. has not been located. FNA 3 mapped it in n. Ky. for unknown reasons. This species may also be expected in the Cumberland Mts., since it is known from adjacent parts of Appalachian states; e.g. in "The Cedars" of Lee Co., Va. (D. Boone, pers. comm.).