Weed of the Month: Bitter Sneezeweed

Bitter sneezeweed contains toxins that can cause digestive disturbance, appetite loss, and neurologic problems in horses.

Photo: Sandi Eisenmenger

Common name: Bitter sneezeweed
Scientific name: Helenium amarum (Raf.) H. Rock

Life Cycle: Warm season annual
Origin: United States
Poisonous: Yes

Bitter sneezeweed is distributed across much of the United States, from Texas north to Kansas and Missouri and eastward to the Atlantic coast. It grows frequently in pastures and can infest entire pastures in western portions of Kentucky. Overgrazing increases the abundance of bitter sneezeweed. Seed germination occurs in late spring or early summer. The plant's leaves are narrow and threadlike and alternate along the stem. The flowers are bright yellow and bloom from late June through September under Kentucky growing conditions.

This species contains toxins that might cause digestive disturbance, appetite loss, and neurologic problems. Horses generally avoid eating bitter sneezeweed, and most problems occur in the late summer when the plant is flowering.

Bitter sneezeweed can be controlled with herbicides. Mowing will reduce seed production but generally is not effective in killing this plant. Hand weeding is effective to remove small infestations. Consult your local Cooperative Extension Service personnel for herbicidal control in your area.

William W. Witt, Emeritus Professor, Weed Scientist, University of Kentucky, provided this information.

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