Poisonous Plants: Watch for These Pesky Plants

If you are someone who likes to go on long hikes while exploring the great outdoors, then you have probably seen your fair share of plants and trees. But as you may know, all plants are not created equal. While many plants that are beautiful to behold, there are still a few that can cause you quite a bit of pain or even serious harm if you are not careful. Here are some plants that are native to southern Ontario that you should avoid like the plague while out in the woods.

Poison Ivy

Many people are familiar with this toxic plant and know that they should avoid it at all costs, but it isn’t always easy to spot poison ivy. One way to help yourself out is to remember the saying “leaves of three, let it be.” This mnemonic reminds you that poison ivy’s distinctive three-leaf pattern is what you need to avoid – and, in turn, the inflammation of the skin that isn’t easy to lose.


This truly unique poisonous plant looks like something that belongs on another planet. Its distinctive appearance features a red trunk-like stem and large ovoid leaves, with flowers that appear white-green. When fruiting, the berries start green and become a dark purple and black during maturation. This plant is also incredibly toxic – both to humans and animals – with symptoms of poisoning exposure ranging from heavy sweating and blurry eyesight to more serious abdominal pains, weakness, vomiting and even loss of consciousness.

Giant Hogweed

Giant hogweed is, well, giant, and can reach a towering 4 to 5 meters in height, as OurWindsor reports. This plant isn’t native to the region, and beyond simply being an invasive newcomer, it also comes with a serious defense – severe burns. The sap of hogweed contains a substance – furocoumarins – that can cause serious burning sensations if it comes into contact with your skin and is exposed to sunlight. Watch for the red-purple stem and whitish flowers that bloom from June to September.

Wild Parsnip

The wild parsnip is another poisonous plant that you should try to avoid. It can be identified by its mitten-shaped leaves and its distinctive parsnip odor – hence the name. This plant also contains the same substances as giant hogweed, which means that coming in contact with this plant could result in the destruction of cells and skin tissues that leads to blisters and redness – ouch!

Spotted Water Hemlock

Often found in swamps, stream banks and ditches, the spotted water hemlock’s weapon of choice is called cicutoxin, a terrible toxin that strikes the central nervous system. Despite the innocent appearance of this plant – a green-purple stem with toothy leaves that bloom to an upside-down umbrella-like formation of tiny white flowers – exposure to it can result in deliriousness, violent convulsions, intense abdominal pains and even a coma or breathing failures, with symptoms showing up between half an hour and eight hours following exposure. Avoid this dangerous plant at all costs.

It is incredibly important that you exercise caution when engaging in nature hikes and other activities that might bring you close to these toxic plants. Be sure to wear long pants, stick to the trails and stay up to date on plants that can cause you harm to ensure you stay out of danger. Stay safe out there and happy hiking from Tom and Michel!