Fall mums have come to represent the end of the gardening season as much as snowdrops and daffodils represent the beginning. There are many other perennials which are excellent companions to fall mums and will help with the gradual transition from mid-summer into the fall. As Delphiniums begin to fade it is hard to image how anything can possibly take their place. In my own garden, Lilies, Flowering Onion, Day lilies and Gayfeather are at their flowering peak just in time to bridge the gap until fall flowering asters dominate the landscape. We can attempt to mimic the colours of nature by including late flowering native wildflowers, such as asters and goldenrod, along with some of their introduced and highly ornamental cousins.
Ornamental grasses continue to flower from mid-summer through to the fall.
Both the flower heads and the interesting changes in colour of the foliage, make ornamental grasses a must for the fall garden. Perennial gardens can tend to look untidy in mid to late summer because of the number of plants which are past their flowering season. Spent flowers, seed heads, yellowing and damaged foliage need to be cleared away so that the beauty of the late flowering plants can take over. Early flowering plants, such as Bleeding Heart, Poppies, and Columbine, will die back to their roots in mid-summer. When the foliage has turned yellow, it should be removed and put into the compost pile.