Poisonous Outdoor Plants - Marsh Plants

Subscribe to our free E-Newsletter, "Agri-News" (formerly RTW This Week)Agri-News
This Week
Common Cattail
Typha latifolia

Description: A common weed easily recognized by its iris-like leaves (erect, 1 - 2 cm wide green blades) and its fat, cigar-shaped, brown spike of densely packed wooly fibres. Stems 1 - 2 m tall, grows in marshy areas.

Poisonous Part: Leaves, stems.

Symptoms: Symptoms in humans not reported. It has been known to kill horses.
Glandular Labrador Tea
Ledum glandulosum

Description: An erect, 0.5 m tall shrub. Stems are upright, many branched and have small glands. The oval leaves are 1.5 - 4 cm long, yellow-green and grainy beneath. Has clusters of small, five-petalled white flowers. The common Labrador tea (Ledum groenlandicum) may also possess irritating qualities if consumed in large quantities. These leaves are covered with dense, rusty hairs. Side effects from drinking too much ‘tea’, a drink often made from dried leaves, have been reported.

Poisonous Part: Leaves.

Symptoms: Not documented. Death of sheep has been reported. (Internal poisoning)
Equisetum spp.

Description: Small herbaceous perennials, the stems are rush-like, often hollow and of harsh texture. The plant appears to have no leaves; however, the stems and branches are green. Some horsetails have many branches in whorls; others form an erect, unbranched pencil-like stem. The head is cone-shaped. Grows in damp areas.

Poisonous Part: All parts

Symptoms: Symptoms in humans not known. Livestock deaths have been reported from ingestion of this plant. (Internal poisoning: unknown)
Marsh Marigold
Caltha palustris

Description: A thick, hollow-stemmed marsh plant 20 - 60 cm tall. The stem branches near the top. Produces round or kidney-shaped deep green leaves. The leaf stems become shorter towards the top of the plant. Sprays of brilliant golden-yellow flowers appear early in May.

Poisonous Part: All parts, young plants not poisonous.

Symptoms: irritation and inflammation of the stomach and intestines, salivation, diarrhea, abdominal pain, convulsions. (Internal poisoning: protoanemonin)
Mountain Laurel, Hog Laurel
Kalmia polifolia var. microphylla
Description: A small woody bush, about 5 - 20 cm tall. Stems have few branches and are hairless with a ‘bloom’. The leaves are 0.5 - 1.0 cm long, evergreen and white underneath. The flowers are rose coloured and showy. Found in boggy areas in the Rocky Mountains and northern Alberta.
Poisonous Part: All parts.
Symptoms: Watering of the mouth, eyes and nose, loss of energy, slow pulse, vomiting, low blood pressure, lack of co-ordination, convulsions, paralysis of arms and legs, coma, death. (Internal poisoning: andromedotoxin)
Water Hemlock
Cicuta spp.

Description: A tall marsh plant that may also occur as a weed along moist ditch edges. It is readily recognized by its clusters of thickened roots and drops of yellow oily fluid that ooze from cut tissue. Has smooth hollow stems and compound leaves with toothed leaflets. Flowers are white or greenish, in clusters. The fruit is flattened and has ribs and oil tubes. A highly toxic plant that is easily mistaken for an edible plant because its roots have a pleasant, parsnip-like odour.

Poisonous Part: Leaves, roots.

Symptoms: Stomach pain, nausea, vomiting, diarrhea, elevated temperature, dilated pupils, labored breathing, frothing at the mouth, weak and rapid pulse, tremors, delirium, violent convulsions, death; many cases of loss of human life on record. Can cause poisoning in cattle. (Internal poisoning: cicutoxin)
Water Parsnip
Sium suave

Description: Closely resembles the water hemlock. A herbaceous perennial 0.5 - 1.0 m tall that has hollow, ridged stems. The roots are spindle-shaped and grow in a cluster. The compound leaves have five or more lance-shaped leaflets with sharp serrations. Produces umbrella-shaped clusters of small white flowers. The fruits are slightly flattened and have corky ribs.

Poisonous Part: Foliage.

Symptoms: Symptoms in humans not known. Has caused livestock poisoning. (Internal poisoning: unknown)
Yellow Lady’s Slipper
Cypripedium calceolus var. pubescens

Description: One to three yellow, orchid-like flowers are produced on long stems emerging from leafy bases.

Poisonous Part: Leaves, stems.

Symptoms: Mild skin irritation to painful blisters. (Dermatitis)
Wild Calla
Calla palustris

Description: Well known, but it is usually viewed from a distance because it inhabits moist, boggy areas. The oval leaves grow on long stems all coming from the base of the plant. The flowers consist of a broad leaf-like bract (spathe) behind a club-like spike (spadix). The true flowers are small and crowded evenly over the surface of the spadix. After pollination, the spathe rots away, and the spadix becomes a dense, fleshy head of orange-red berries.

Poisonous Part: All parts, particularly rhizomes.

Symptoms: Intense irritation and a burning sensation in the mouth; death has occurred in animals. (Dermatitis, internal poisoning: calcium oxalates)


Other Documents in the Series

  Poisonous Outdoor Plants - Introduction
Poisonous Outdoor Plants - Garden Plants: Vegetables
Poisonous Outdoor Plants - Garden Plants: Flowers
Poisonous Outdoor Plants - Trees and Shrubs
Poisonous Outdoor Plants - Field Plants
Poisonous Outdoor Plants - Forest Plants
Poisonous Outdoor Plants - Marsh Plants - Current Document
Poisonous Outdoor Plants - References
Share via AddThis.com
For more information about the content of this document, contact Barry Yaremcio.
This document is maintained by Jennifer Rutter.
This information published to the web on November 22, 2010.