Field Guide

Ironweeds are tough, grayish-green, branching plants known for their fluffy-looking clusters of reddish-purple florets. They are a familiar sight on roadsides and pastures. Identify western ironweed by the bracts at the base of the flowerheads.

An invasive native of Eurasia that is spreading in Missouri, musk thistle is a plant you should know. Learn how to tell the difference between our native thistles and these bad guys.

Bull thistle is a weedy introduction from Europe, found statewide. To tell it from our other thistles, note its stems with spiny-margined wings, and its leaves with the upper surface strongly roughened with stiff, spiny bristles.

Tall thistle is a native thistle that can grow to be 10 feet tall! To identify it, notice its leaves, which are unlobed (though they may be wavy or have only shallow, broad lobes), are felty-hairy beneath, and have prickles only along the edges.

Canada thistle is a native to Eurasia and arrived on our continent probably before the Revolutionary War — most likely mixed in agricultural seed. A bad weed of crop fields and rangeland farther north, it causes problems in Missouri, too.

Blue cardinal flower, or blue lobelia, is a showy, late-blooming native wildflower that grows along streams, ditches, sloughs, and other wet places. It has blue or purple tubular flowers with 2 upper lips and 3 lower lips.

Clasping Venus' looking glass is a single-stemmed plant with purple or blue star-shaped flowers and bluntly toothed, alternate leaves that clasp the stem. It's scattered statewide in a variety of habitats and blooms May-June.

False dragonhead is called "obedient plant" because when you push one of the flowers sideways, it "obediently" stays in place for a while.

“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.

Narrow-leaved vervain is a short, slender perennial with single stems or with upper stems sparingly branched. Its many small flowers are crowded on narrow spikes. The corollas are tubular, deep lavender or purple, with 5 spreading lobes.