Poisonous Plants in the United States
The following is an alphabetical list and description of common plants / plant parts poisonous to humans and animals. If poison occurs, call the poison control center or a vet as soon as possible.
Taking walks through my Dallas suburb I can see several types of laurels, rhododendron, azaleas, oleander, iris, tulip, lily, daffodil, jasmine, lantana, holly, poison ivy, elephant ear, wisteria, cherry trees, and oaks.
| Plant | Parts | Symptoms | Plant Description |
| Azalea | All parts | Digestive upset, difficulty breathing, depression, coma, can be fatal (1) | Flowering shrub in the genus Rhododendron |
| Baccharis | Seeds | Digestive upset (3) | Arid shrub in the sunflower family |
| Black locust | Bark, leaves, sprouts | Digestive upset, weakness (1, 7) | Straight tree growing in dry soil and sun, with compound oval leaves, thorns, and white flowers |
| Bleeding heart | Leaves, roots | Can be poisonous in large amounts (1) | Plant of the Papaveraceae family with oddly shaped flowers |
| Boxthorn | Berries | (7) | Thorny nightshade shrub with funnel shaped flowers and berries can be red, black, yellow, or orange |
| Bracken Fern | Foilage | Digestive upset, digestive cancer (2) | Long fronds with spores |
| Buttercup | All parts | Digestive tract damage (1,5, 7) | Small water loving perennial with bright yellow, sometimes white flowers |
| Calla Lily | All parts | (7) | Plant of the Araceae family with trumpet like flowers, usually white |
| Cape tulip | All parts | Can be fatal (7) | One-leafed plant with lily like flowers |
| Castor Bean | Seed | Extremely poisonous and one seed can be fatal (1,3, 7) | Ornate leaves, unusual flowers, spiny seed |
| Celandine | Juice | Lung, liver, and nervous system sedative and can be fatal (7) | Tall perennial plant with yellow flowers that have four pedals |
| Cherries | Twigs and leaves | Difficulty breathing, can be fatal (1) | Scaled bark, oval leaves, small dark round berries |
| Chinaberry | Berry | Digestive upset (3) | Small tree with toothed leaflets, pinkish flowers, and green fruit |
| Comfrey | Essential Oil | Can cause liver damage (7) | Perennial herb with hairy broad leaves and small bell shaped flowers |
| Common Box | Leaves and bark | (7) | Evergreen tall shrub with highly aromatic green flowers |
| Crocus | Bulb | Vomiting, nervousness (1) | Perennial flower with a cupped shaped early Spring bloom |
| Daffodil | Bulb | Ingestion can cause nausea, vomiting, diarrhea, may be fatal (1) | Spring flower that is yellow or white with a long leafless stem and stalk leaves |
| Daphne | All parts | Fatal in small doses (1,7) | Evergreen shrub with non petaled often green flowers that have four or five petaloid sepals |
| Delphinium | All parts | (7) | The plant has an iris like flower and deeply lobed palmate leaves |
| Elderberry | leaves, twigs, unripe berries | Digestive upset (1) | Decorative shrub with clustered white flowers and small black berries |
| Elephant ear | All | Extremely poisonous causing burning of the tongue and mouth, can cause swelling that blocks air passages and may be fatal (1) | Herb with large elephant ear shaped leaves |
| European Beech | Nuts | (7) | Tall tree with grey smooth bark and brown nuts |
| Fetterbush | Leaves and flowers | Digestive upset, convulsions, possible death (3) | Shrub with oval leaves and small flowers |
| Foxglove | Leaves and seeds | Heart rate, digestive pain, mental confusion, can be fatal (1, 7) | Hairy leaved, bell shaped herb with pink flowers |
| Goldenseal | All parts | Toxic in excess (7) | Plant in the buttercup family with two palmate hairy leaves and a single small flower |
| Golden chain | All parts, especially seed pod | Convulsions, coma, may be fatal (1, 7) | Small tree with trifoliate leaves and yellow ornamental flowers |
| Hellebore | All parts | Weakness, digestive upset, cardiac irregularity, possible death (7) | Hardy flower, can be evergreen, with beautiful five petal flowers |
| Henbane | All parts | Confusion, cough, rapid heart rate, can be fatal (7) | Toothed leaves, yellow flowers, strong aroma |
| Holly | Berry | (7) | Bush with hard thorny leaves and red berries |
| Horsenettle | Berries, leaves | Gastrointestinal lesions (3) | Thorny shrub with unusual leaves, white or purple flowers, and tomato like fruit |
| Horse Chestnut | Nut | (7) | Tree with large leaves, white flowers, and thorny nuts |
| Hyacinth | Bulb | Ingestion can cause nausea, vomiting, diarrhea, may be fatal (1) | Spring flower with 4-6 ong leaves and a few spikes filled with flowers |
| Indian tobacco | All parts | Toxic in excess (7) | Hairy leaved, blue flowered biennial |
| Inkweed | Berries, leaves, roots | (7) | Tall woody plant with pointed leaves and dark purple berries |
| Iris | Root / stem | Digestive pain (1) | Tall decorative flower with a leafless long stem and stalk leaves |
| Ivy | Berries | Nervousness, troubles breathing, coma, possible death (7) | Evergreen vine with triangular leaves |
| Jack in the Pulpit | All parts | Intensely burns mouth and tongue (1) | Forest flower with trifoliate leaves and unusual tubular greenish flower. |
| Jasmine | All parts | Digestive upset, difficulty breathing, depression, coma, can be fatal (1) | Perennial vine with evergreen leaves and yellow fragrant flowers |
| Jimsonweed | Whole plant, especially the seeds | Can cause hallucination and be fatally toxic (4, 7) | Tall shrub with toothed leaves, tubular flowers, and a strong aroma |
| Kowhai | All parts, especially seeds | (7) | Small tree with yellow drooping flowers and pods with wings |
| Lantana | Green berry | Can be fatal (1, 3) | Shrub with prickly stem and multicolored flowers |
| Larkspur | Seeds | Digestive pain, nervousness, can be fatal (1) | Tall flowering perennial that bears many dark purple flowers on its stalk |
| Laurel | All parts | Digestive upset, difficulty breathing, depression, coma, can be fatal (1, 7) | Tall shrub with thick evergreen leaves and pink flowers |
| Lily of the Valley | All parts | Heart rate, digestive pain, mental confusion (1, 7) | Spring plant with 5-15 white bell shaped flowers on a stem and one or two long leaves; the berry is round and orangish red |
| Maleberry | Leaves | Possible death (3) | Shrub with elliptic serrated leaves and white flowers |
| May Apple | Fruit, leaves, root | Can cause digestive upset (1, 7) | Forest ground plant with parachute shaped leaf small apple like fruit |
| Mexican Poppy | Seed | Edema, weakness addictive, and possible death (3, 6, 7) | Spiney small desert flower with bright showy flowers |
| Milkweed | All parts | Can be fatal in high doses (3, 7) | Spreading plant with thick rootstocks and seeping milk |
| Mistletoe | Berry | Can be fatal (1, 7) | Parasitic vine with waxy oval leaves and berries |
| Monks Hood | All parts, especially the Root | Digestive pain, nervousness, can be fatal (1, 7) | Hairy stemmed perennial with blue flowers |
| Moonseed | Berry | Can be fatal (1) | Woody vine shrub with triangular leaf and blue colored berry |
| Ngaio | Leaves and fruit | (7) | Small tree with purple spotted flowers and oblong fruit |
| Nightshade | All parts | Intense digestive upset, nervousness, can be fatal (1, 3, 7) | Purple bell shaped flowers, black berries, and pointy leaves |
| Oak | Leaves, acorn | Can cause kidney damage over time (1) | Tall tree with acorns |
| Oleander | Leaves, branches | Ingestion can affect the heart and digestive system, extremely poisonous and can cause death (1, 3, 7) | Flowering coastal shrub with ornamental flowers |
| Poison Ivy | Leaves | Skin and mucous membrane irritant (3) | Climbing vine with three pinnate leaves |
| Poison Hemlock | All parts | Can be fatal (1, 7) | Tall weed with white flowers and delicate leaves |
| Poison Oak | Leaves | Skin and mucous membrane irritant (3) | Low climbing shrub with thick hairy leaflets |
| Poison Sumac | All parts | Skin and mucous membrane irritant (3) | Small tree with pinnate alternating oblong leaves |
| Pokeweed | All parts | Gastric pain, convulsions (3) | Large perennial with large fleshy stems, big leaves and round black cluster strands of fruit |
| Privet | Fruit and leaves | (7) | Shrub with white flowers and black berries |
| Ragwort | All parts | (7) | Weed like plant with stinky yellow flowers |
| Rattlebox | Seeds | Depression, irregular heart rate, digestive upset (3) | Tall shrub with large winged leathery pods |
| Red Buckeye | Seeds and leaves | Digestive upset, trembling, weakness, possible death (3) | Small tree with oval leaflets, carlet flowers, and leathery fruit |
| Rhododendron | All parts | Digestive upset, difficulty breathing, depression, coma, can be fatal (1) | Evergreen shrub with ornamental spring blooms |
| Rhubarb | Leaves | Convulsions, coma, can be fatal (1, 7) | Plant with leaf stalks, leaves are long and triangular and stem is red |
| Rosary Pea | Seed | Extremely poisonous and one seed can be fatal (1) | Known for its lady bug like hard seeds, it also has rows of oval leaves and red flowers |
| Rue | All parts | Toxic in excess (7) | Decorative plant with bluish leaves and small flowers |
| Sassafras | Essential oil, root | Digestive upset, can be toxic (7) | Aromatic tree with leaves that have three oval prongs, yellow flowers, and drooping blue/black fruit |
| Sesbania | Seeds | Heart rate, digestive upset 93) | Woody herb with small oblong leaflets, yellow flowers, and linear pods |
| Sicklepod | Seed | Digestive upset (3) | Yellow flowered herb with sickle shaped pods |
| Sneezeweed | All parts | Digestive upset (3) | Perennial herb with lanceolate leaves and yellow flowers |
| Star of Bethlehem | Bulb | Vomiting, nervousness (1) | Small bulbed white flower with six petals and green stripe on the outside |
| Tansy | Essential oil | Can be fatal (7) | Flower in the daisy family with yellow button flowers that smell camphorous |
| Thorn Apple | All parts | Thirst, blurred vision, confusion, coma, can be fatal (1) | Shrub with spiked leaves and sharp spiked fruit |
| Water Hemlock | All parts | Convulsions, and potential death (1, 3) | Perennial herb with purple striped stem and white lacy flower |
| White Snakeroot | Leaves | Trembling, Delirium (3) | Perennial herb with simple oval leaves and white flowers |
| Wisteria | Seeds, pods | Digestive pain (1) | Ornamental flowering climbing vine with pod seeds |
| Wormwood | Essential Oil | Can cause death if ingested (7) | Perennial with a fibrous root, silver green leaves, and yellow flowers |
| Yew | Leaves, berries | Can cause sudden death (1) | Small evergreen tree with distinctive bright red berries that turn to smooth seed-cones |
References
- Texas A&M Agrilife Extension (n.d.). Common poisonous plants and plant parts. Retrieved in January 2017. Retrieved from http://aggie-horticulture.tamu.edu/earthkind/landscape/poisonous-plants-resources/common-poisonous-plants-and-plant-parts/
- Voss, J. University of Colorado. (2017). Guide to poisonous plants. Retrieved in January, 2017. Retrieved from https://csuvth.colostate.edu/poisonous_plants/Plants/Details/50
- Miller, J. F., Kates, A. H., Davis, D. E., & McCormack, J. (1980). Poisonous plants of the southern United States. Poisonous plants of the southern United States. Link: https://carteret.ces.ncsu.edu/wp-content/uploads/2013/05/Poisonour-Plants-of-the-Southern-United-States.pdf?fwd=no
- Spina, S. P., & Taddei, A. (2007). Teenagers with Jimson weed (Datura stramonium) poisoning. Cjem, 9(06), 467-469.
- Turner, N. J. (1984). Counter-irritant and other medicinal uses of plants in Ranunculaceae by native peoples in British Columbia and neighbouring areas. Journal of ethnopharmacology, 11(2), 181-201.
- Steyn, D. G. (1950). Poisoning with the seeds of Argemone Mexicana (Mexican poppy) in human beings: Indian epidemic dropsy in South Africa. South African Medical Journal, 24(18), 333-339.
- American College of Healthcare Sciences (January, 2017). Poisonous Plants. Course material from Herb 502 Class.
