Hiker walking through a forest

How to do anything: spot dangerous plants

You’ve packed everything on your hiking checklist, and have reviewed maps for the area you’re going to explore. All ready to go? Almost. If you’re headed for backcountry travel in Canada, you’ll encounter all sorts of plants, some of which are beautiful to look at but can be highly dangerous to touch.

Stay safe – and rash-free – on your hiking or camping trip by keeping an eye out for these five plants you might come across in the wild:

Poison ivy

Poison ivy plant

Poison ivy is most common in southern Ontario and Quebec, although it can be found in every Canadian province with the exception of Newfoundland. The plant grows as a vine or a shrub along rivers, lakes, meadows, forest openings and beaches.

The leaves change colour throughout the seasons. During the summer, poison ivy is a shiny green, making it easy to blend in with other plants. A simple way to identify poison ivy is to remember the phrase, “Leaves of three? Let it be.”

Avoid it because: Urushiol, a liquid in the plant’s sap, creates a skin rash on anyone who touches the plant.

Giant hogweed

Giant hogweed plant

Present across the country – in British Columbia, Ontario, Quebec, New Brunswick, Nova Scotia and Newfoundland – giant hogweed is a firm, bright green plant that grows in ditches and open woodlands, alongside streams, and in other areas with moist soil.

Typically 2–5m in height, the plant has large leaves with serrated edges and a hollow leaf stalk with dark red spots and prickly hair. Giant hogweed also produces an umbrella-like top that contains small, white flowers.

Avoid it because: The chemicals in giant hogweed make skin sensitive to sunlight after contact and can cause large burns and blisters (along with a visit to the doctor).

Stinging nettle

Stinging nettle plant

Spread throughout Canada, stinging nettle typically grows in damp areas like marshes, meadows, pastures and ditches.

Stinging nettle, which grows 1m or more in height, can be identified by clusters of fuzzy white flowers and serrated leaves. These plants have sharp, thin hairs, which operate like hollow hypodermic needles and allow toxins into the skin upon contact.

Avoid it because: Contact with the plant causes itching, numbness and swelling, leading to a painful rash.

Canada moonseed

Canada moonseed berries

Found in Manitoba, Ontario and Quebec, Canada moonseed appears in thickets, beside streams and along bluffs. It grows as a climbing vine, up to 6m in height.

Canada moonseed has green leaves – containing 3–7 lobes each – and purple-black berries, which some people have unfortunately mistaken for wild grapes. (Canada moonseed has crescent moon-shaped seeds, while grapes contain round seeds.)

Avoid it because: Ingesting Canada moonseed berries is bad news – they lead to convulsions, seizures and possibly death.

Water hemlock

Water hemlock plant

One of the most deadly plants located in most of Canada, water hemlock can be seen near marshes, pastures, rivers and streams.

The plant can grow up to 1–2m in height, and has a hollow, branching stem with a spotted purple pattern. It produces white flowers clustered together in the shape of an umbrella. It’s occasionally mistaken for edible roots such as wild parsnip; pick up a plant field guide to learn how to distinguish the difference.

Avoid it because: Water hemlock is fatal if ingested. It contains cicutoxin, an extremely toxic chemical that can disrupt the central nervous system. If you see someone accidentally consume this plant, treat it as a life-threatening situation and seek emergency medical help immediately – it’s serious and can cause death within as little as 15 minutes.

Being able to identify plants you come across in the backcountry is an excellent skill. Not only can it help you avoid unsafe species, it also gives you all sorts of appreciation for the huge variety of flowers, trees, grasses and bushes you might not otherwise notice.

Use a plant field guide to get familiar with the local species you may encounter as you venture through the lush wilderness of Canada’s backcountry.

Photo credits: John (Flickr), debs-eye (Flickr), John Neon, “Moonseed fruit 1” by Nadiatalent is licensed under CC BY-SA 4.0, Wendell Smith

Tony Xu, writer
Tony Xu

Wearer of many hats and helmets: writer, CSIA level 3 ski pro, data geek, backcountry explorer, rookie rock climber. Driven to tell stories that bring the adventurous spirit out of everyone.