Perennials are a wonderful addition to any garden and can provide color and interest throughout the year. The top 5 players in the late-season garden would have to be asters (Aster), chrysanthemums (Dendranthema), goldenrods (Solidago), Joe-Pye weed (Eutrochium) and stonecrops (Sedum). Below is a longer list to keep your garden in color throughout the fall season.
*These plants are not in bloom during September and October, but they have ornamental value, for either seedheads or colorful foliage.
Growing Perennials in Cold Climates by 
Understanding Perennials by 
Perennials: the gardener's reference by 
Diseases of Herbaceous Perennials by 
Armitage's Garden Perennials by 
The Well-Tended Perennial Garden by 
The Perennial Gardener's Design Primer by 
