This perennial plant is 1-2½' tall, branching occasionally to abundantly. The stems are light green, terete, and appressed-pubescent. The opposite leaves are up to 3" long and 2" across; they have short slender petioles. The leaf blades are oval-cordate, oval, or ovate in shape, while their margins are dentate or dentate-crenate. The upper blade surface is light green and glabrous with a conspicuous network of veins. The upper stems terminate in flat-topped clusters of flowerheads. Each cluster of flowerheads spans about 1-3" across. Each flowerhead has about 40-50 disk florets that are pink, lavender, or blue. Each floret has a tiny tubular corolla with 5 spreading lobes and a strongly exerted style that is divided into two filiform parts. Around the base of each flowerhead, there are several floral bracts (phyllaries) that are arranged in 1-2 series; they are light green and linear in shape. The branches underneath each flowerhead cluster are light green and terete. The blooming period occurs from mid-summer to early autumn, lasting about 1-2 months. There is no noticeable floral scent. Afterwards, the florets are replaced by achenes with small tufts of hair; they are distributed by the wind. The root system is highly rhizomatous; this plant readily forms colonies.