Poisonous Outdoor Plants - Field Plants

This section lists a variety of plants, many of them considered weeds that are known to cause livestock poisoning. Livestock poisoning can occur easily because the animals often ingest large quantities when grazing or when being fed hay or silage.

Many of the plants listed below have not been known to cause human poisoning. However, as more urban people unfamiliar with wild plants spend more of their time getting back to nature, the potential for human poisoning increases.

In most cases, large quantities of the plant need to be ingested to cause poisoning. Livestock are also susceptible to poisoning by some plants that are able to accumulate toxic materials such as nitrates and selenium; however, these plants are not listed here.

..Plant	..Poisonous Part	..Type of Poisoning/ ..Toxic Agent
Arrowgrass Triglochin maritima and T. palustris	All parts	Internal poisoning: cyanogenetic properties
Bahia Bahia oppositifolia	Foliage	Internal poisoning: cyanogenetic glycoside
Black henbane Hyoscycamus niger	All parts, especially roots	Internal poisoning: several alkaloids (mainly hyoscyamine)
Bittersweet (climbing nightshade) Solanum dulcamara	Immature fruit, leaves	Internal poisoning: solanine
Buttercup Ranunculus spp.	All parts, except seeds; toxicity lost on drying.	Internal poisoning: dermatitis/protoanemonin
Cocklebur Xanthium strumarium	Seeds, seedlings	Internal poisoning: hydroquinone
Docks, sorrels	Leaves, stems	Internal poisoning: soluble oxalates
Rumex spp.
Dogbane family
Indian hemp Apocynum cannabinum	All parts	Internal poisoning: resins and glycosides (primarily cymarin)
Spreading dogbane Apocynum androsaemifolium	All parts, especially rhizomes	Internal poisoning: resins and glycosides (primarily apocynamarin)
False ragweed Iva xanthifolia	Leaves	Dermatitis
Field bindweed (Wild morning glory) Convolvulus arvensis	Seeds	Internal poisoning
Golden bean Thermopsis rhombifolia	Seeds, leaves	Internal poisoning: quinolizidine alkaloids
Greasewood Sarcobatus vermiculatus	All parts	Internal poisoning: soluble oxalates
Green tansy mustard Descurainia pinnata	All parts	Internal poisoning: unknown
Ground ivy Glechoma hederacea	All parts	Internal poisoning: volatile oils
Groundsels Senecio integerrimus, S. vulgaris	All parts	Internal poisoning: pyrrolizidine alkaloids
Jimson weed (thorn apple) Datura stramonium	All parts, especially seeds and leaves	Internal poisoning: solanaceous alkaloids
Locoweeds and milk vetches Oxytropis and Astragalus spp.	All parts	Internal poisoning: locaine
Mallow Malva parviflora	All parts	Internal poisoning: malvalic and sterculic acids
Milkweeds Asclepias spp.	All parts	Internal poisoning
Mustard family
Black mustard Brassica nigra	All parts	Internal poisoning: isothiocyanates
Canola (rapeseed) Brassica napus	All parts, raw and in large quantities	Internal poisoning: isothiocyanates
Indian mustard Brassica juncea	All parts	Internal poisoning: isothiocyanates
Wild mustard Brassica kaber	Seed or podded plants	Internal poisoning: isothiocyanates
Wormseed mustard Erysimum cheiranthoides	Seeds	Internal poisoning: allyl isothiocyanate
Pasque flower (prairie crocus) Anemone patens	All parts	Internal poisoning: ranunculin
Prickly lettuce Lactuca serriola	Young fresh plants are poisonous; mature plants and young stages after drying appear to be non-toxic.	Internal poisoning: unknown
Ragweed Ambrosia spp.	Pollen	Hay fever
Sagebrush Artemisia spp.	All parts	Internal poisoning:unknown
Silverleaf psoralea Psoralea argophylla	Seeds	Internal poisoning
Spurges Euphorbia spp.	Sap	Dermatitis, internal poisoning
Stinkweed Thlaspi arvense	Seed, leaves	Internal poisoning: allyl isothiocyanate
Tarweed (fiddleneck) Amsinckia spp.	Seeds	Internal poisoning: unknown liver toxin
Viper’s bugloss (blueweed) Echium vulgare	Bristly hairs on leaves and stems	Dermatitis

Poisonous Outdoor Plants - Field Plants

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