Field Guide

White snakeroot looks very similar to thoroughworts, but it has triangular leaf blades that are more broadly angled or rounded at the base. White snakeroot is common statewide. It’s a toxic plant if eaten, so it’s good to be able to identify it.

American, or common boneset has small, white flowerheads in flat-topped clusters at the top of the plant. The leaves are hairy, narrowly triangular, and in opposite pairs fused around the stem.

A stout perennial that can grow to 6 feet tall, tall thoroughwort is a member of the sunflower family that has dull white flowers and distinctive leaves that are opposite, slender, very short-stalked, and with three quite noticeable veins.

Mist flower, or wild ageratum, is a vigorous native perennial bearing fluffy-looking, bluish-purple flowerheads. It looks quite a bit like the annual ageratum that is sold as a bedding plant in garden centers.

Swamp milkweed has pink flower clusters at the tips of its tall stalks. The leaves are opposite, narrow, and up to 6 inches long. It grows in moist bottomland soils.

The flowers of purple milkweed are pale purple to reddish purple to dark purple, with greenish or red tints. The scientific name means “becoming purple”: The flowers start off rather pale and become more intensely purplish as they mature.

Soapwort is a tall, showy wildflower that has chemicals in its sap that lather up like soap. Native to Eurasia, it has been introduced worldwide and is a common roadside wildflower.

Indian hemp is a shrubby, upright perennial with opposite branches and milky sap. This native plant can be a troublesome weed in crop fields and gardens, but Native Americans used its tough, fibrous stems for rope-making.

In Europe, St. John’s-wort was long used as a medicinal herb and to ward off evil magic. Today, researchers are finding it can treat depression. Yet it poisons livestock and in some places is an invasive weed.

“Infestation” is the term for what teasels are doing in Missouri. Learn to identify these thistlelike plants, and help to control the weedy spread of these tough, prickly invaders.