Bishop’s Weed (Aegopodium podagraria) is a tenacious, fast-spreading perennial ground cover in gardens and yards across North America and Europe. This invasive species is a member of the carrot family, Apiaceae, and is known as Goutweed and Ground Elder. Its aggressive spreading habit often leads homeowners to attempt removal, raising public concern about its safety. Because the plant mimics several highly poisonous relatives, understanding the true nature of Bishop’s Weed is a matter of practical safety.
Is Bishop’s Weed Poisonous to Humans and Pets?
Bishop’s Weed is considered non-toxic or minimally toxic, lacking potent alkaloids. Ingestion by humans typically results in mild gastrointestinal upset, such as nausea, vomiting, or diarrhea, if large quantities are consumed. The plant has historically been used in some cultures as an edible herb, with its young leaves added to salads in the spring. This traditional use supports its low-risk profile in small amounts.
For common household pets like dogs and cats, the risks are similarly low. While not severely toxic, consumption may lead to temporary symptoms like stomach upset or loose stools. Pet owners should still consult a veterinarian if any unusual or persistent symptoms occur after ingestion.
Identifying Bishop’s Weed
The plant typically grows as a dense, low ground cover, usually reaching heights between one and three feet when flowering. Its stems are hollow and noticeably grooved, supporting the leaves and flower clusters. The leaves are basal, meaning they emerge near the ground, and are divided into three groups of three leaflets, creating a ternate structure.
These leaflets are oval, pointed at the tips, and have serrated edges. Many cultivated varieties feature variegated leaves, displaying creamy-white margins. During the late spring and early summer, Bishop’s Weed produces small, white flowers clustered in flat or dome-shaped arrangements called umbels. This umbrella-like flower structure is characteristic of the Apiaceae family.
Dangerous Look-Alikes and Misidentification Risks
The greatest danger posed by Bishop’s Weed stems from its close resemblance to several deadly members of the Apiaceae family. This group contains some of the most poisonous plants in North America, including Poison Hemlock (Conium maculatum) and Water Hemlock (Cicuta maculata). Misidentification is a potentially fatal error that necessitates extreme caution.
Poison Hemlock
Poison Hemlock is significantly taller, often reaching heights of nine feet, and is distinguished by its stems. Unlike the plain, ridged stems of Bishop’s Weed, Poison Hemlock has smooth, hairless stems covered in distinctive purple or reddish-purple mottling or blotches. Its leaves are also much more finely divided, resembling delicate parsley or fern fronds.
Water Hemlock
Water Hemlock, another highly toxic look-alike, grows primarily in wet habitats like marshes and stream banks. While its flowers also appear in white umbels, its leaf veins end in the notches between the teeth, rather than at the tips. The toxin in Water Hemlock, cicutoxin, is concentrated heavily in the roots and can cause violent convulsions and death if ingested.
Because the flowers of all these plants share a similar umbrella shape, identification should never be made based on the flowers alone. Confirmation must rely on the plant’s full set of features, including height, habitat, leaf structure, and stem markings. Careful observation is paramount for anyone foraging or clearing weeds.
Emergency Response to Ingestion
If any person ingests Bishop’s Weed or, more significantly, a plant suspected to be one of its deadly look-alikes, immediate action is required. Contact Poison Control (1-800-222-1222) or seek emergency medical care without delay. If a pet is involved, contact a veterinarian or a dedicated Pet Poison Helpline immediately.
It is extremely helpful to collect a small sample of the plant, including any flowers, stems, or roots, to aid in positive identification by medical or veterinary professionals. Since no antidote exists for the toxins in Poison Hemlock and Water Hemlock, treatment focuses on supportive care, such as managing symptoms and preventing the body from absorbing more of the poison. Exposure to the sap of some Apiaceae family members, such as Giant Hogweed, can also cause a severe reaction called photodermatitis, which is skin blistering following sun exposure. Handling any unknown plant should be done with gloves to prevent potential skin irritation.