Giant hogweed

Giant hogweed is a tall, invasive perennial plant that grows in limited areas in New Brunswick. Its hollow stem is very bristly, with purplish colored spots or blotches. When fully grown, its leaves can be up to 1.5 metres wide and 3 metres long, with white flowers clustered in an umbrella shape.

Giant hogweed can be harmful to people and pets when touched. Its clear watery sap contains toxins that, when exposed to sunlight, cause skin inflammation, burns and a rash (photodermatitis). If this sap comes in contact with the eye, it can cause temporary blindness.  

There are many plants that are similar in appearance to giant hogweed such as cow parsnip and Wild parsnip that do not have the same level of health risk, as they produce less chemicals.  

Giant hogweed

Giant hogweed typically grows very tall, from 1.5 to 5 metres in height. Its leaves are shiny and large, with very coarse and serrated leaf edges, like a jagged saw edge. The stems are very hairy, bristly and covered with purple blotches. The plant produces flowers that form a large umbrella shape, up to 1.5 metres in diameter.

Cow parsnip

Cow parsnip is a native species in New Brunswick. It is typically shorter than giant hogweed, about 1-3 metres tall, with leaves that are smaller and less toothed. The stems of cow parsnip are woolier and usually plainer green, without spots. Cow parsnip is common in moist or wet soils in a wide variety of habitats throughout the province. A slight rash (dermatitis) can result from contact with this plant, but it typically causes much less severe symptoms than giant hogweed. 

Angelica 

Angelica plants are typically 1-2.5 metres tall with large, compound leaves made of smaller rounded or elliptical leaflets. The stems are usually smooth and purplish in colour while the round flower heads are much smaller than giant hogweed flowers. Angelica may cause slight a slight rash (dermatitis). Woodland angelica is an introduced and invasive species more common throughout the Saint John River valley in wet, weedy habitats. Seacoast angelica and purple Alexanders are native species more commonly found in coastal areas and in the northern interior, respectively.

Wild parsnip 

Wild parsnip is typically much shorter, only growing to 0.5 to 1.5 metres in height. The leaves have sharp teeth that can be misshapen. This plant is more branched than the other members of this family and has very distinctive yellow flowers. Wild parsnip is an introduced species and is common along roadsides throughout New Brunswick. The sap of this plant can cause a poison ivy-like reaction in sensitive individuals, most commonly noticed following whipper-snipping plants while not wearing proper protection.

Valerian 

Valerian grows to a height of 1 to 2 metres. Its leaves are divided like wild parsnip, but the individual leaf segments are much longer. The mature flowers are clustered and white to purple in colour. The seeds of valerian are similar to dandelion seeds and can be the easiest way to correctly identify this plant. Valerian is a highly invasive species occurring most commonly through the southern region of New Brunswick.

If you come in contact with giant hogweed, be sure to:

• wash affected area immediately with soap and cold water, then wash your hands
• cover up affected areas and keep them out of direct sunlight for at least 48 hours
• change and wash your clothes to prevent spread
• seek medical attention as soon as possible
• if your eyes come in contact with the sap, rinse your eyes thoroughly with clean water for 10 minutes, wear dark sunglasses to avoid exposing your eyes to the sunlight and seek medical attention as soon as possible 

For any allergic reaction or serious symptoms, call 911 or go to the nearest emergency room.