Solidago rugosa var. aspera, Thick Rough-leaf Goldenrod Native, Piedmont & coastal plain Leaves thick, firm, wrinkled, not sharp-toothed, with short stiff hairs.
Solidago rugosa var. rugosa, Thin Hairy Rough-leaf Goldenrod Native, Piedmont & coastal plain Leaves thinner, less wrinkled, sharp-toothed, long-pointed, smooth or with soft hairs. More common than var. aspera, especially in the Piedmont.
Solidago bicolor, White Goldenrod Native, Piedmont & coastal plain Flowers are white.
Solidago hispida, Hairy Goldenrod Native, Piedmont only Similar to S. bicolor, but with yellow flowers. Stem and leaves hairy. Dry open woods, rocky slopes.
Delaware Wildflowers
Two have flower heads in axillary clusters or on short branches
Solidago flexicaulis, Broadleaf Goldenrod 
Seventeen have flower heads in terminal panicles
Solidago arguta var. arguta, Cutleaf Goldenrod 
Solidago rugosa var. rugosa, Thin Hairy Rough-leaf Goldenrod 
Five have flower heads in a long terminal cluster
