Poison Ivy, Oak, and Sumac: All About the Itch
By: Julie Day
If you enjoy working or playing outdoors, chances are you’ve come in contact with either poison ivy, poison oak, or poison sumac. And if you’re like me, you’ve likely experienced the irritating rash that comes from handling these poisonous plants. Here are some tips for identifying, removing, and coping with poison ivy and its relatives in the lawn and garden.
Three asymmetrical leaves and a hairy stem point to poison ivy.
Identifying Poisonous Plants
Poison ivy, oak, and sumac are commonly found in woodland areas, naturalized beds, river banks, and growing up trees, but they also can show up in the most manicured of gardens. They all have temptingly colorful foliage in the fall, and offer the same allergic reaction when handled or cut. Poison ivy and oak have similar growth patterns while poison sumac is a bit different.
The adage “Leaves of Three, Let It Be” is actually a good suggestion. Poison oak and ivy are master imitators, taking on the leaf shape of the plants around them and making them difficult to identify. The three-leaf pattern gives them away, so you’re safer staying away from any three-leafed plant unless you’re sure it isn’t poisonous.
A large poison ivy vine growing up a tree.
Poison Ivy and Poison Oak
Poison ivy is a climbing or sprawling vine that can also grow upright. It has three broad leaves at the end of each stem, either straight or slightly lobed, with greenish-white flowers and small white berries in summer, along with hairy-looking roots attaching it to trees that give it away in the winter when the leaves are not present. Older leaves often have a slight distinctive lobe along the edges.
Like poison ivy, poison oak usually has a cluster of three broad leaves, though it can have up to seven. The leaves tend to be glossy, and the plant grows upright.Western poison oak has lobed leaflets like an oak tree, while eastern poison oak is more like a glossy version of poison ivy.
Poison oak and poison ivy can be difficult to tell apart, and the leaf shape varies from region to region. For help identifying them, check with your local agricultural extension service, or go to Poison Oak Photos and Poison Ivy (about.com).
Poison sumac is an upright shrubby plant with long, arching stems with up to 13 smooth, feather-shaped leaflets along each stem. The red stem distinguishes poison sumac from other types of sumac. It tends to grow in wet areas such as creek beds, swamplands, and coastal areas. It’s more common in the coastal southeast but can grow in boggy woodlands. For help identifying this plant, check out these Poison Sumac Pictures (about.com).
Two Innocent Bystanders
- Virginia creeper is a common woodland plant that is frequently mistaken for poison ivy. It has five feather-shaped leaves and isn’t poisonous. However, if you’re in an area where Virginia creeper grows, there’s a good chance poison ivy is nearby!
- Kudzu is another aggressive, nonpoisonous vine with a suspicious three-leafed pattern. Its leaves are larger and smoother than poison ivy, but again, they frequently grow in the same area.
Facts About Poison Exposure
- Poison ivy, oak, and sumac contain a toxic oil called urushiol. When the plants are touched, this oil can be released onto the skin.
- Every part of the plant is poisonous, even if the plant is dead.
- The oil can best be compared to Super Glue. It sticks to your skin and penetrates within 30 minutes. Once it’s bonded, it isn’t coming off until the itchy rash finally sloughs off the toxins over a period of days or weeks, helped along by the miserable scratching of its victim.
- As irritating and uncomfortable as the rash may be, even more dangerous reactions can occur from breathing or ingesting the chemical, particularly when the plants are burned.
- The most common means of exposure are from touching or pulling the plants, but you can also be exposed when lawn mowers throw the oils into the air, or through an intermediary, like pets who’ve brushed up against the plants.
- The poison ivy rash is not contagious and does not spread by breaking the blisters. It only spreads through contact with the actual plant oil, although rashes can worsen over time, so it feels like it’s spreading.
Poison plants are difficult to eradicate.
Getting Rid of Poisonous Plants
- Hand pulling: The most effective way to get rid of poison ivy/oak/sumac is to pull or dig it up, but most of us are too sensitive to do this without getting infected. Work carefully when the ground is soft and wet, to have a better chance of getting all the roots.
- Smothering: Another organic method involves cutting the vines close to the ground, then smothering them with plastic, newspaper, or carpet scraps. This can be a way to sterilize large areas but takes a long time to work.
- Chemical herbicides: Glyphosate works fairly well, or you can try stronger “brush killers” containing triclopyr and 2,4-D. Herbicides can be sprayed or painted on the foliage, or painted on the cut ends of larger vines. They may need to be reapplied to make sure it’s all gone. For best results, use herbicides when the plants are fully leafed out in spring and summer, and make sure to target the plants on a non-windy day.
Tips for Working Around Poisonous Plants
- If you’re working around poisonous plants, wear gloves and long clothing to prevent skin exposure.
- Train yourself not to wipe your brow or otherwise touch your skin with your gloves!
- Immediately after exposure, scrub skin thoroughly with plenty of soap and cool water, or with an urushiol-removing soap such as Tecnu.
- Wash clothes and gloves, immediately after use, in hot water with regular detergent.
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