Heracleum maximum is toxic to cats, dogs and horses. The reported severity is mild. Also known as Common Cowparsnip and Tube Clematis.
If your animal ate this plant, call your veterinarian, the ASPCA Animal Poison Control on (888) 426-4435 or the Pet Poison Helpline on (855) 764-7661. Fees may apply.
Dermatitis Photosensitivity
The color of each symptom follows the severity scale above.
Heracleum maximum, commonly known as cow parsnip, is the only member of the genus Heracleum native to North America. It is also known as American cow-parsnip, Satan celery, Indian celery, Indian rhubarb, poison turnip or pushki.
The plant contains furanocoumarins such as xanthotoxin, angelicin, pimpinellin and isopimpinellin, isoimperatorin, bergapten and isobergapten, 6‐isopentenyloxyisobergapten, and sphondin. In one study, the young leaves did not contain xanthotoxin, but older, senescing leaves contained "substantial amounts". Some of these furanocoumarins found in cow parsnip are known to have antimicrobial properties and are responsible for a rash producing erythematous vesicles (burn-like blisters) and hyperpigmentation that occurs after getting the clear sap onto one's skin. They are photosensitive, with the rash occurring only after exposure to ultraviolet light. Because of this, phytophotodermatitis causing skin blistering may occur after coming into contact with the sap on a sunny day. The scars and pigmentation from these blisters caused by some Heracleum species can last for months or years.
Also recorded as American cow-parsnip, American hogweed, Cow Parsnip, Indian celery, Pushki and masterwort.
More from the Apiaceae family:
Countries with the most wild observations, from GBIF data.