This is an illustration of how the introduction of one stunning colorful plant can give tired, end of season borders a boost. A fresh splash of color draws the eye and gives an entirely new perspective on the fading summer scene. In this article by Lauren Dunec Hoang which I found on the Houzz website there are five suggested plants that can be used to create an impact in this way.

Imagine the impact of a pot of brightly blooming flowers set on your doorstep. The eye is immediately drawn to the color, skimming over other areas of the porch, perhaps not noticing details like peeling paint or steps in need of a sweep. In the same way, adding just one colorful perennial or a shimmering ornamental grass can rejuvenate a worn-out late-summer garden bed.
In need of an end-of-season boost? Take a look at how planting a single fall favorite, such as gold-petaled black-eyed Susan or purple fountain grass, can gracefully transition beds from summer to fall.

Genevieve Schmidt

?Autumn Joy? Stonecrop
(Sedum ?Autumn Joy?)This easy-care plant is a popular choice for fall gardens, with good reason. Its standout blooms come into their own in September, turning from pale green to rosy pink and then to deep pomegranate, just as many other summer flowers are beginning to fade. Sticking just one of these clumping perennials into a garden bed will immediately draw the eye and the attention of butterflies and other pollinators.

Paintbox Garden

?Autumn Joy? stonecrop with fountain grass (Pennisetum alopecuroides)
Pair it with: Ornamental grasses and fine-leaved perennials, such as artemisia or thyme. The contrast in textures between stonecrop?s succulent leaves and chunky flowers and feathery grasses or small-leaved plants makes for a standout combination.
Where it will grow: Hardy to minus 35 degrees Fahrenheit, or minus 37.2 degrees Celsius (USDA zones 3 to 10; find your zone)
Water requirement: Moderate; low once established
Light requirement: Full sun to partial shade
Mature size: 1? to 2 feet tall and wide
 

Field Outdoor Spaces

Black-Eyed Susan
(Rudbeckia hirta)The cheerful golden-petaled and dark-centered blooms of black-eyed Susan, also called gloriosa daisy, enliven late-summer and fall borders. The plants, native to prairies of the central United States, are much beloved by butterflies. Cultivars may be available at your local nursery, producing flowers in shades of red, bronze and orange and with bicolored petals.

Paintbox Garden

Pair it with: For a fall bouquet garden, pair black-eyed Susan with other late-summer blooms that work well as cut flowers, such as shasta daisy (Leucanthemum x superbum; shown here with black-eyed Susan), annual sunflowers, chrysanthemums and coneflowers (Echinacea spp.).
Where it will grow: Hardy to minus 35 degrees Fahrenheit, or minus 37.2 degrees Celsius (zones 3 to 7)
Water requirement: Moderate; low once established
Light requirement: Full sun
Mature size: 2 to 3 feet tall and 1 foot to 2 feet wide