Touch-Me-Nots: Common Poisonous Plants in Your Yard

Summer is finally here! Are you itching to get out and about in your yard? Learn to spot and avoid these troublemakers.

Poison Ivy

“Leaves of three, let it be” is an oft-heard phrase when learning about poison ivy, but beware! Sometimes poison ivy does not have leaves of three.

Poison ivy has a notoriously plastic habit (plastic meaning variable, and habit meaning pattern of growth). It can grow along the ground, or upward like a shrub, and sometimes it covers trees like a vine. Sometimes the three leaflets grow close together and look like one leaf, and sometimes they grow far apart and look like three separate leaves.

So, how do you spot poison ivy?

There are three things to look for:

Poison ivy has little red hairs all along the stem. These might be darker or lighter depending on the season and the health of the plant, but if the stem is smooth, you know it’s not poison ivy.
Poison ivy leaves are often in groups of three, and the smaller leaves at the top of the plant look shiny. The shine is caused by an oil the plant secretes called urushiol. This oil is what makes you itch. If you get it on you or your clothes, be sure to wash with an oil-cutting soap like dish soap and avoid anything with moisturizer because it can spread it around. The larger lower leaves may also appear shiny, or the shine may have worn off.
When poison ivy grows up from the ground, it has a wiggly look—like a snake being charmed out of its basket. Most other plants curve in one direction, branch or grow straight up. This wiggle is a good visual cue for identifying poison ivy before its leaves are out, or after the leaves have dropped, so you can avoid walking through the area. Remember those red hairs listed above? Those hairs are covered in urushiol too, so even if the plant has no leaves you can still get itchy if you brush up against it.

Some Other Touch-Me-Nots to Know

Creeping nightshade, also known as bittersweet nightshade, is a common weed in southeast Michigan and its vines can grow to 3 feet or more. Its dark green leaves can cause severe contact dermatitis to those who are sensitive, and its berries are highly toxic to both humans and animals. Look for the bright purple flowers with yellow centers to help identify it.

Giant hogweed is another one to watch out for. It is relatively uncommon, but is spreading. It looks like an enormous version of Queen Anne’s lace, and can be up to 14 feet tall. Contact with the sap causes blistering, and if you get it in your eyes it can be blinding. The reaction is worse with exposure to light, so if you think you’ve encountered it, be sure to wash it off and avoid sunlight for the next 24-48 hours.

Poison sumac is found in some areas of Michigan's lower peninsula. Like poison ivy, it’s shiny, but it has way more than three leaflets per leaf. Luckily, it’s mostly found in swampy areas, so if your feet are dry you are probably safe.

Poison oak rounds out the poison trio, but it is rarely found in the Midwest. If you do stumble across it, it has a lot of the same characteristics as poison ivy so it should be easy to spot.

Stinging nettle looks nothing like poison ivy. You’ll feel a sharp sting, followed by a burning or itching sensation that can last up to a whole day after you touch it. It tends to grow in dense patches, and it has a furry look from all of the white stinging hairs underneath and on top of the dark green leaves.

Ragweed reactions are less serious, but you are much more likely to encounter it. Ragweed typically flowers in mid-August, and most folks know it as the plant that makes them sneeze; however, if you walk through it with bare legs or spend time with it in the garden, you know it can cause itchy red streaks or even blisters that can last a few days. You can spot ragweed by its fern-like leaves. It can get very tall, like hogweed, but it is usually 3-4 feet high.

You may also have a reaction or sensitivity to other plants or even grass. Whatever the cause, don’t itch if you can help it. Running the affected area under cool water can help, as can cooling creams like calamine lotion. Before you apply a cream, be sure to wash the area with something like dish soap to remove any lingering oil.

Of course, if it’s been a few days and it just won’t stop itching—or if it covers large portions of your body—see your doctor. There may be a non-plant cause, or they may be able to prescribe something that can help.

Want to see what to avoid? Check out the pictures below and leave these plants alone!

Poison Ivy

Stinging Nettle

Giant Hogweed

Common Ragweed