Citronella Horsebalm. Collinsonia canadensis L.

Figure 39.—Citronella horsebalm (Collinsonia canadensis)

Other Common Names

Stoneroot, Collinsonia, knob-root, knob glass, knobweed, knotroot, horseweed, richweed, richleaf, ox balm.

Habitat And Range

Citronella horsebalm is found in moist shady woods from Maine to Wisconsin and south to Florida and Kansas.


This plant is a tall herb growing as high as 5 feet with a stout, erect, branched stem, smooth or the upper part hairy. The leaves are from 3 to 8 inches long, pointed, sometimes heart-shaped at the base, and coarsely toothed. From July to October the plant produces large, loose panicles of small pale-yellow, lemon-scented flowers. The entire flowering herb possesses a pleasant, lemonlike odor. The root, even when fresh, is very hard, hence the name stoneroot. It is horizontal, large, thick, and woody, the upper side rough, knotty, and irregularly branched. It has a rather disagreeable odor and a spicy, pungent taste.

Part Used

The root, collected in autumn.