7 Poisonous Weeds to Avoid That Might Be Lurking In Your Yard
7 Poisonous Weeds to Avoid That Might Be Lurking In Your Yard
You love being outdoors, camping, hiking, or just digging around in your garden with your gardening gloves. But some plants can cause serious allergic reactions. “Most poisonous plants are of concern because of the risk of livestock, such as sheep or cattle, grazing on them,” says Mark Czarnota, Ph.D., associate professor and extension weed scientist at the University of Georgia. ‘’But there are a number of plants that can cause serious skin reactions or respiratory issues in humans, too, depending on the sensitivity of the individual. Knowing how to recognize these plants is the first step to protecting yourself.” To get a positive ID, do an online search, or talk to your local university coop extension service agent (find yours here), who can advise control methods if you’ve found the plant in your yard.
When you brush up against a plant you suspect (or know!) is poisonous, cleanse the area gently with cool water and soap ASAP (no vigorous scrubbing, which can make things worse). A few over-the-counter products, such as Tecnu Poison Ivy Scrub and Ivy X Post Contact Cleanser, may prevent or reduce skin reactions if used immediately after suspected exposure. Clothes should be washed with detergent because they can transfer plant oils to furniture or other household items, says Czarnota. Ditto for garden gloves, tools, and pets! For example, if your fur baby ended up in a patch of poison ivy, bath him or her as soon as possible so you don’t pick up the oils (fortunately, pets rarely have reactions unless they’re a hairless breed).
If a rash appears, which can develop in a few hours to week after contact with a poisonous plant, ease itchiness with cool compresses, topical over-the-counter hydrocortisone cream and calamine lotion, and oral antihistamines. Most rashes last 2 to 3 weeks. But if you’re in severe discomfort or the rash is worsening, call your doctor for a prescription.
Many of these poisonous weeds are in the same family but may look slightly different depending on the species and region of the country. However, here are the most common poisonous weeds you’re likely to encounter when hiking or gardening:
1) Poison Ivy
Where you’ll find it: Widespread but often in or along the edges of moist, deciduous forests
What it looks like: Woody perennial that grows as a small shrub or climbing vine on trees, fences or buildings. Three bright green leaflets are arranged alternately on the stem, though leaves of different shapes may be found on the same plant. May have white flowers on slender stalks which become grayish-white berries in late summer.
Poison ivy is one of the most common poisonous plants in the country, accounting for more cases of contact dermatitis than all other plants and household products! Chemicals in the plant, such as urushiol, are present in all parts of the plant including stems, leaves, roots, flower and fruits. Contact with the plant often causes contact dermatitis such as a red, blistered or itchy rash. Fortunately, only the oily toxin can spread the rash, not the fluids from the blisters. In addition, some people can have a reaction in the lungs or nasal passages if the plant is burned for disposal.
2) Poison Oak
Where you’ll find it: Widespread in urban, coastal and woodland areas
What it looks like: Dense deciduous shrub or a climbing vine. The leaves may have three leaflets, five or seven leaflets with a coating of fine hair. The leaflets are 1 to 4 inches long with toothed or lobed edges, reminiscent of an oak leaf. Whitish flowers become tan berries in late summer.
This native plant is sometimes difficult to identify due to the variation in leaflet patterns. Poison oak contains urushiol, the same chemical in poison ivy, that causes contact dermatitis in people who are sensitive to it. Usually, the plant must be damaged in order for plant to release the oil such as if you’re clearing brush, pruning, or using a string trimmer. It also can cause severe respiratory irritation if burned.
3) Burning or Stinging Nettle
Where you’ll find it: Uncultivated areas such as riverbanks, roadsides, fence rows and cultivated areas such as gardens, orchards and vineyards
What it looks like: Depending on the type, it’s a small to medium-sized broadleaf annual weed with stinging hairs or a tall perennial broadleaf weed that grows in large colonies. Stinging hairs are present on both types.
This native plant has fine or bristly hairs on the stems and leaves that cause irritant dermatitis. Unlike poison ivy or poison oak, which cause a reaction only in people who are sensitive to it, this plant affects everyone! The hairs are made from a tubelike structure with a bulb on the end; when the bulb makes contact with skin, the bulb breaks off and causes a needlelike injection of a toxic substance (probably a histamine), causing reddish patches accompanied by itching and burning, which can last more than 12 hours.
4) Giant Hogweed
Where you’ll find it: Along streams or in woods in the Northeast, Mid-Atlantic, Canada and Pacific Northwest
What it looks like: A member of the carrot or parsley family, these plants can reach 15 to 20 feet tall at maturity with leaves that are up to 5 feet wide. The thick stems have white umbrella-shaped flowers.
You may have read about this invasive species because of its horrifying dermatological effects. Introduced in the early 1900s as an ornamental, giant hogweed sap contains furanocoumarins, a chemical present in all parts of the plant including the stems and hairs on the stems that causes photosensitivity. When the sap contacts skin and is exposed to sunlight, severe skin inflammation and painful blisters erupt within 48 hours. The blisters often last for months, and the affected area may develop long-term sensitivity to sunlight.
5) Nightshade
Where you’ll find it: Gardens, woods, field edges and roadsides
What it looks like: This plant may be erect or vining with purple bell-shaped or white or purple star-shaped flowers with bright yellow anthers. The fruit is dark purple-black or red, depending on the species.
There are many different species of nightshade with similar appearances, depending on the region. But all parts of any nightshade plant are poisonous; the purple-black berries probably are the biggest risk because curious kids or pets may eat them. Handling the plant also can cause dermatitis in people who are sensitive to it.
6) Poison Hemlock
Where you’ll find it: In moist shaded areas such as along roads, streams, trails, ditches, and forest edges
What it looks like: The plant has stout stems with purple spots, small white flowers in umbrella-shaped clusters, and fern-like leaves. It’s usually 3 to 10 feet tall by the second year.
This invasive plant, which was introduced as an ornamental plant in the 1800s, is a biennial (lives two years) that spreads by seed. All parts of this plant are poisonous to humans and animals, it’s often confused with wild carrot or wild cow parsnip. But neither of these plants have purple spotting. Poison hemlock contains alkaloid compounds which can be fatal if ingested (people have accidentally eaten it thinking it was wild carrot or parsnip). The sap is also a skin irritant or respiratory irritant for some people.
7) Oleander
Where you’ll find it: Alongside highways or as a landscape planting in USDA zones 7 and warmer; sometimes also grown as a houseplant
What it looks like: A perennial, evergreen shrub or small tree with sharply-pointed leathery leaves, oleander has showy white, pink or red flowers with 5 or more petals.
Oleander is a beautiful, drought-tolerant plant often used as landscaping in warm climates, but every part of this plant is toxic to both people and pets. Strangely enough, people have been poisoned by using the long, straight branches as cooking skewers! The thick, sticky sap also can cause contact dermatitis. If you have this plant in your landscape, keep curious kids and pets away from it, and don’t plant it near animal enclosures.
The weeds you should avoid in your yard, on hikes and during camping trips—whether it’s the entire plant, just the seeds, or something else.