Many perennial gardens peter out in mid-summer and limp into the fall, tattered, overgrown and virtually devoid of bloom. The traditional potted chrysanthemums and ornamental kale or cabbage (Brassica oleracea var. acephala) offer autumn freshness and color, but several late-blooming perennials can do the job equally well, if not better.

This group of late bloomers includes reliable plants such as tall Sedum 'Autumn Joy', a garden workhorse whose rosy broccoli-like flowers are bee magnets in the fall. Newer sedum selections, such as 'Matrona' and 'Black Jack' with their burgundy-tinged foliage and 'Frosty Morn' with its green-and-white variegation, offer extra interest. 

The various "Helis"—Helianthus, commonly known as sunflower, Heliopsis, common name oxeye, and Helenium, also called sneezeweed or Helen's flower—are additional stalwarts of the late-summer to early-fall garden, blooming in yellows, and in the case of Helenium, shades of orange, red and rust as well. Perennial asters in purples and pinks are cooler color options for later in the season.

Besides these mainstays, there are several lovely but surprisingly less well-known perennials that can provide flowers and structural interest in the autumn garden.

Japanese anemones (Anemone hupehensis, A. tomentosa and hybrids) are elegant fall bloomers that prefer a moist and semi-shady spot. (These spread, so site them carefully.) From a mound of grape-like leaves rise tall stems topped with fresh and delicate single or semi-double blooms in pinks, purples and whites.

In moist soil, Chelone, or turtlehead, grows into a 3 ft. (0.9m) glossy clump with pink or white flowers that resemble a snapdragon or, as its name suggests, a turtle's head.

Joe Pye weed (Eupatorium species and cultivars) are tall plants, native to North America, that remind me of refined milkweeds. They prefer moist soil, and their flattish flower clusters are very attractive to butterflies. Commonly available cultivars include E. maculatum 'Selection' or 'Gateway', both with pink flowers, E. fistulosum 'Bartered Bride', with white flowers, and E. rugosum 'Chocolate', with brownish-purple foliage and white flowers.Another plant to keep in mind is sedem. The burgundy-tinged foliage of sedum adds color to the fall garden.

If you saw a single blossom of the sweet autumn clematis (which may be labeled as Clematis terniflora, C. ternifolia, C. paniculata or C. maximowicziana), you would not likely rush out to buy one. But see that blossom en masse with hundreds of others in a long-lasting fragrant white cloud, and you'll be hooked. This approximately 15 ft. (4.5m) vine flowers on the current year's growth in early autumn and pairs beautifully with fall-red Virginia creeper (Parthenocissus quinquefolia).

There are many additional fall-flowering perennial and bulb choices. An autumn visit to local display gardens and nurseries will give you some ideas for alternatives to potted mums that will carry your perennial garden through to the frost with freshness, structure and color.