Field Guide

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.

In early spring, henbit carpets entire fields with the pinkish-purple of its small flowers. This nonnative mint spreads abundantly but causes few problems. It has shallow roots and fades before crops begin to grow.

Sometimes called wild oregano, dittany, like true oregano, is a member of the mint family and can be used as a culinary herb and in teas. Look for it on dry, wooded slopes in Ozark counties.

Next time you breeze past weedy black mustard on the highway or spot it in a fallow field, think of how important this and other mustards are to the world economy – and to your dinner table.

Wild potato vine is related to the sweet potatoes we buy at grocery stores. This native vine is also related to the morning glories that decorate trellises and to the bindweed that plagues gardeners and farmers.

Square, unbranching stems, opposite leaves, two-lipped flowers, and a mild minty fragrance are clues Ohio horsemint is in the mint family. Tight, rounded flower clusters are stacked atop one another at the stem tips.

A square-stemmed plant with opposite leaves, self-heal bears two-lipped blue, lavender, or violet flowers in a cylindrical head. We have two varieties of self-heal in Missouri, one native and one introduced.

At first glance, you might overlook corn salad, except for the large colonies it often forms. The young leaves can be eaten as a salad green, hence the name.

Toothwort is a member of the mustard family that blooms March–May in wooded slopes and valleys. The sharply toothed, deeply lobed leaves are distinctive. The bright white, 4-petaled flowers shine at forest visitors.