Prairie gerardia, Prairie agalinis

Agalinis heterophylla (Nutt.) Small ex Britt. & A. Br.

Scrophulariaceae (Foxglove family)


Prairie gerardia is a native, warm-season annual in the Foxglove family. It is also commonly named prairie agalinis or grass killer, because it can shadow and suppress lower growing grass.

The plant grows to about 3 feet tall. A key characteristic of prairie gerardia is that its stems turn black when the plant dies in the summer or fall.

Depending on moisture, the purple tubular flowers appear in the summer, late summer and generally the fall.

The forage value of this plant is low for livestock and fair for wildlife.


Prairie gerardia is found mainly on prairies, plains, grasslands, open woodlands and fallow fields.