Choose some late blooming daylilies like Sandra Elizabeth
Of course a Limelight Hydrangea will delight you through the summer, fall and winter.
Mary Todd Daylily has been trimmed down and a couple of weeks after it is time to pull out all of the brown stems you see to the left and voila you have a fresh green plant again!
Heucheras are in their glory this time of year not only for their colorful leaves, Pistache, but for the airy flowers they produce.
This is one of my favorites, Heuchera Purpurea, not so much for the leaves but their flowers are wonderful.
Heuchera Raspberry Ice is a very hardy one also with pink flowers.
Keep cutting the spent flowers down to the ground on heuchera and they will bloom throughout the fall.
Max Frei Geranium is interesting in that when you deadhead it in the early summer it just sits until now when it begins flowering again.
Look for shrubbery that has interest through more than one season like Ninebark Summer Wine.
This is another multi-season shrub Dark Horse Weigela, pink flowers and dark bronze leaves for three seasons.
You can extend the season with other non-flowering perennials like the ferns that are anything but green.
Japanese Painted Fern is one that is showy throughout the spring, summer and fall in my area, great colors that are more appreciated in the fall.
Autumn Fern becomes more showy in the fall with some of the fronds taking on an orange glow.