Field Guide

Shepherd’s purse is a plant that started in Europe and western Asia and has been introduced nearly worldwide. Like the common dandelion, it has several adaptations that make it a successful colonizer of disturbed soil.

A spiny annual with bright yellow flowers and dandelion-like leaves, buffalo bur is an introduced member of the nightshade family.

Pretty but poisonous, jimsonweed has white goblet-shaped flowers that open around midnight. This native of tropical America was introduced nearly throughout the United States and thrives in disturbed soils.

A biennial plant with bristly hairs and usually with single stems, viper’s bugloss can grow 2½ feet tall. The flowers are pink in bud, blue to ultramarine later. The protruding stamens are pink.

Prickly sida, a weedy plant seen along roadsides, streambanks, and the edges of fields, is in the same family as hibiscus, okra, and hollyhocks. A small, spinelike projection grows at base of each leaf.

Horse nettle is a native perennial with spiny stems and leaves, white to purplish flowers, and toxic fruits that look like tiny yellow tomatoes. It does well in disturbed habitats, and many people consider it a weed.

Horseweed looks something like a goldenrod, except that the tiny composite flowers are not yellow. Instead, they are cream-colored and rather drab. In Missouri, this plant is especially associated with disturbed habitats and is a troublesome crop weed.

Ox-eye daisy, though familiar, is not native to North America. It was introduced long ago from Eurasia. Common in grassy uplands, pastures, fencerows, and roadsides, it can colonize aggressively in the garden.

Our weediest sneezeweed, bitterweed arrived in Missouri in the late 1800s from its home range in Texas and Louisiana. Like our other heleniums, it has domed disks and yellow, fan-shaped, notched ray florets. Unlike them, the leaves are narrowly linear.

Native to Ozark glades and prairies, tickseed coreopsis has long been appreciated as a hardy garden perennial. Because of its popularity, it has escaped from cultivation and now occurs statewide.