Variety hargeri is uncommon in more mesic locations in eastern North Dakota, South Dakota, and Nebraska. The more hairy-stemmed race of the species, it is more common in the southern and western portion of its range, where it can completely replace var. canadensis. It can be very similar to diploids of Solidago altissima subsp. gilvocanescens, which normally have thicker, sparsely toothed to entire distal cauline leaves. Reports from other more southern and western states are likely based on plants of S. altissima.
From Flora of Indiana (1940) by Charles C. Deam
This form is found in various habitats ranging from alluvial banks, open woods, and crests of hills to roadsides. It is difficult to separate from forms of Solidago altissima.