There is no shortage of plants that bloom in spring and through to the peak of summer. But by the time September rolls around, the garden may be looking a bit shaggy. There are species that put on their annual show at this time of year, but they are relatively few in number so you may have to seek them out and intentionally intersperse them in among the earlier bloomers.
Here's a round-up of five of the best.
This eastern US native grows and grows and grows all summer long before erupting with 4- to 6-inch burgundy blooms once the stalks are 6 feet tall. If you don't have that much space, don't worry, there are numerous shorter cultivars, including 'Little Joe', which grows just 2 feet tall. USDA zones 4 to 9.
Asters are another wildflower that does its thing in late summer and early fall. They are known for their star-shaped purple or sky blue blossoms with a yellow 'eye' in the middle. They are one of the easiest perennials to grow and will often seed themselves to become naturalized in the garden. USDA zones 4 to 9.
Goldenrod is a third wildflower that no list of fall-blooming perennials would be complete without. This North American native grows 3 to 4 feet tall with nodding spikes of dusty yellow flowers that emerge just as the days start to feel shorter and the nights cool down. Their color goes perfectly with the first turning leaves of fall. USDA zones 4 to 9.
Now for a couple more exotic options
Pineapple sage grows 4 to 5 feet tall before releasing its crimson red flowers late in the season—they are a welcome buffet for any hummingbirds they may still be hanging around. The fragrance of the foliage is delicious and the leaves can actually be made into a tasty tea. Pineapple sage is only hardy in USDA zones 8 to 11, but if you start it early enough in spring, it will bloom as an annual.
Cannas are one of the most colorful perennials available. They come in a variety of warm colors, ranging from yellow to orange to pink to red. Many cultivars have variegated or richly dark leaves, as well. The flowers appear atop the lush vertical stalks of foliage in mid to late summer and often continue blooming into early fall. Cannas are hardy in USDA zones 7 to 11, but they grow from tubers which can be dug up and stored for the winter in colder climates.