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Pest SolutionsPESTS + WEEDSUSING PESTICIDES OR HERBICIDES?
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Poison oak
Toxicodendron diversilobum
Updated Oct 27, 2024
Make a Positive Identification
- Poison oak is a woody shrub or vine that grows in woodlands and grassy hillsides. In drier locations it grows in chaparral.
- The leaves have three leaflets ranging from smooth edges to lobed, and are often shiny.
- In the fall the leaves turn bright red. Poison oak loses its leaves in the winter.
Touching poison oak leaves or stems causes skin irritation, rash, and itching (dermatitis) on most people. Touching contaminated clothes, tools, and pets also results in a reaction.
Burning poison oak plants releases oil in the smoke. Don’t breathe smoke from burning poison oak plants. Severe irritation of the mouth, throat, and lungs may result.
After working or traveling in an area with poison oak, take steps to minimize exposure to the oil:
Wash your skin to remove the oil as soon as possible after exposure to poison oak.
Remove clothes and shoes and wash them separately from other clothing.
Wash tools and pets that come in contact with poison oak plants.
Soap and plenty of cold running water work to remove the oil from your skin. A solvent like isopropyl alcohol also works.
A product called Tecnu® Skin Cleanser effectively washes away poison oak oil from your skin, pets, clothes, and tools.
Wash your skin to remove the oil as soon as possible after exposure to poison oak.
Remove clothes and shoes and wash them separately from other clothing.
Wash tools and pets that come in contact with poison oak plants.
Soap and plenty of cold running water work to remove the oil from your skin. A solvent like isopropyl alcohol also works.
A product called Tecnu® Skin Cleanser effectively washes away poison oak oil from your skin, pets, clothes, and tools.
Poison oak
Species: Poison oak
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
Poison oak can grow in the form of a woody shrub.
Species: Poison oak
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
It grows as a vine on trees and structures. The vines can also run along the ground.
Species: Poison oak
"Pacific poison oak (Toxicodendron diversilobum)" by Franco Folini is licensed under CC BY-SA 2.0
The leaves of poison oak alternate along the stem. They have three leaflets that can have smooth or lobed edges. The leaves are often shiny. They are purplish brown when they first emerge. They turn green when fully developed.
Species: Poison oak
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
In the late summer and fall, leaves turn orange and red.
Poison oak Benefits
- Poison oak is a natural part of the environment. Birds eat the berries. It provides habitat for animals.
Poison oak Risks
- Touching poison oak leaves or stems causes dermatitis on many people.
- Contact with contaminated clothes, tools, or pets will cause a reaction.
- Burning poison oak plants releases oil in the smoke. Don’t breathe smoke from burning poison oak plants. Severe irritation of the mouth, throat, and lungs may result.
Risk Card
Does it cause harm?
Adults & Children
High
Causes skin irritation and rash
Property
Low
Native plant
Pets
High
Oil on pets can spread to people
Annoyance
High
Environment
Low
Action Optional
Take Action?
If you have poison oak growing on your property in a place where you can’t tolerate it, take action to control it.
Do I need to take action?
It depends. Consider controlling it near homes and recreational areas. Otherwise, leave it alone.
What if I do nothing?
Poison oak seeds are spread by birds, and it will continue to grow where it is.
Prevent Poison Oak
"Poison Oak" by Trevor H is licensed under CC BY-NC-SA 2.0
Look for New Poison Oak Plants
- Return to areas where you treated poison oak and look for regrowth.
- Poison oak seeds are dispersed by birds. Look for poison oak seedlings like the plant shown in the photo. Also look for poison oak in hedgerows, fence rows, and re-vegetation projects.
- Remove new poison oak plants before they become established.
Weston Miller, Oregon State University
Replant the Affected Area
- After poison oak is removed, desirable plants that it covered often regrow.
- Poison oak removal activities may seriously damage a site. There may be few or no desirable plants remaining.
- Replanting may be needed. Replanting stabilizes the soil surface and shades poison oak seedlings.
- Plant with a variety of native species.
- Check plantings yearly for new poison oak plants generated from bird droppings.
- Plan for at least 2-3 years of monitoring and maintenance.
- For help contact your local extension specialist, soil and water conservation district, or a professional re-vegetation specialist. They can suggest strategies for your area.
- Look for poison oak growth at any time of the year.
- Managing large stands requires several years of followup monitoring and treatment.
Solutions for Poison Oak
Physically Remove Plants
Dig out individual plants and small patches. Remove the roots. Allergic people should not handle poison oak.
Grazing by Goats and Sheep
Goats and sheep are used by land managers to control poison oak.
Herbicides (Weed Killers)
Herbicides effectively control poison oak when used according to the label instructions.
Monitoring and Follow-Up
Look for poison oak growth at any time of the year.
Managing large stands requires several years of follow-up monitoring and treatment.
NEED HELP?
Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.
Jump to
| Method | Does it work? | Is it safe? | Recommendation |
|---|---|---|---|
A Physically Remove Plants |
Effective |
Moderate risk |
Use if Necessary |
B Grazing by Goats and Sheep |
Effective |
Low risk |
Recommended |
C Control with Herbicides |
Effective |
Moderate risk |
Use if Necessary |
|
D If Using Herbicides, Protect Yourself & Minimize Risks
|
A
Physically Remove Plants
Non-Chemical Method
Weston Miller, Oregon State University
Physically Remove Plants
Use if Necessary
DIGGING OUT POISON OAK WITH HAND TOOLS
When handling poison oak use gloves and protective clothing.
Dig out individual plants and small patches. Remove the roots.
| Does it work? | Effective |
| How much effort? | High effort
|
| What's the risk? | Moderate risk
|
| Possible risk of exposure or harm from chemicals | NONE |
Poison Oak Removal Tips
- Cut stems near the ground and dig out root crowns and rhizomes.
- Be careful to manage your exposure to the oils present in all above ground parts of the plant.
- Don’t burn the debris but let it compost in piles over a long time.
- The oils can remain for a number of years in the debris depending on how quickly it decays.
B
Grazing by Goats and Sheep
Non-Chemical Method
Scott Bauer, USDA Agricultural Research Service, Bugwood.org
Grazing by Goats and Sheep
Recommended
Goats and sheep are used by land managers to control poison oak.
| Does it work? | Effective
|
| How much effort? | Moderate effort |
| What's the risk? | Low risk
|
| Possible risk of exposure or harm from chemicals | NONE |
Contact professional pest control companies with experience grazing goats to control poison oak. Or ask your Soil and Water Conservation District office for referrals.
"Poison oak lunch" by Alan Vernon is licensed under CC BY-NC-SA 2.0
C
Control with Herbicides
Chemical Method: Use with caution
Chameleonseye, iStock
Control with Herbicides
Use if Necessary
| Does it work? | Effective
|
| How much effort? | Moderate effort
|
| What's the risk? | Moderate risk
|
| Possible risk of exposure or harm from chemicals | El uso de herbicidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos. You may be exposed to an herbicide if you:
Follow directions closely to reduce risk. |
Some herbicides are available for home use. A few are listed below. These active ingredients, used individually or in a mixture, are suggested chemical treatments to control poison oak. Look for these chemical names in the “Active Ingredients” section of product labels.
- 2,4-D + Dicamba
- Glyphosate, Isopropylamine salt
- MCPP-P
- Quinclorac
- Sulfentrazone
- Triclopyr
Suggested active ingredients are from the Pesticide Information Center Online (PICOL) Database. They are permitted for HOME use in Oregon. Read the label for application directions and effectiveness information.
ONLY professional pesticide applicators can use Restricted-Use Pesticides (RUP) that may be more effective. For larger stands of poison oak contact a licensed pesticide applicator with experience controlling poison oak.
Herbicide Application Tips
- Most of these ingredients will damage most plants and grasses. Don’t let the spray contact plants you want to keep.
- The best time to treat poison oak depends on the herbicide you use.
- Herbicide treatments are less effective if the plants are drought stressed.
- Expect that poison oak will re-grow from the roots after treatment with herbicides.
- Monitor the area for regrowth and re-treat every year, if needed.
Minimize the potential impact of herbicides to bees and other pollinators. Treat poison oak plants before they flower. If plants are flowering when you need to treat them, use the cut-stump or basal bark herbicide application technique. Avoid spraying pollinators directly. For more information, see OSU’s How to Reduce Bee Poisoning from Pesticides.
Herbicide Application Methods
Foliar (leaves), bare stem (basal bark), and cut-stump application methods all effectively kill poison oak. Choose the right method for your situation.
James H. Miller, USDA Forest Service, Bugwood.org
James H. Miller, USDA Forest Service, Bugwood.org
Lyon Duong, UF/IFAS
If Using Herbicides, Protect Yourself & Minimize Risks
Chemical Method: Use with Caution
BrianLasenby, iStock
Why is it important to read herbicide labels?
- They have detailed information on how to use the product correctly and legally.
- They contain information on potential hazards of the product.
- They provide instructions you should follow for poisonings and spills.
- Following label instructions helps you to minimize the risks and maximize the benefits.
Key Herbicide Safety Tips
- Read the entire label front to back.
- Follow the instructions.
- Review the instructions even for brands you know.
- Only apply the product where the label says it may be applied.
- Be precise in your application. More is not better.
The Label is the Law
ALWAYS read the label before using herbicide products. The label is a legal document that provides information on how to safely use the herbicide. This helps avoid harm to human health and the environment. Using an herbicide in off-label ways is illegal. It can result in legal enforcement actions.
READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.
- Labels are different for every product and they often change over time.
- Use a magnifying glass for small print.
- Pay attention to CAUTION, WARNING, and DANGER statements.
- Pay attention to the PRECAUTIONARY STATEMENTS.
- The law states you must read and follow herbicide instructions.
Protect Yourself
Eye, skin & lung irritants
- Wear the right protective gear. This often includes chemical-resistant gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
- Mix outdoors or in a well-ventilated area.
- Wash hands after mixing or applying, and before eating or smoking.
- Take a shower immediately after handling herbicides.
- Wash clothes worn while mixing or applying separately from other laundry.
Protect Children & Pets
Children and pets are at risk if they eat or touch the plants before it dries.
- Keep them away during and after applying herbicides (read label for how long).
- Remove toys and pet dishes from yard before applying.
- Don’t track herbicide products into your home on shoes or clothes.
Protect Plants You Want to Keep
- Glyphosate and similar herbicide ingredients damage both grass and broadleaf plants.
- Minimize spraying of foliage, stems, exposed roots, or the trunks of desirable shrubs or trees to avoid harm.
- Follow the label to avoid damaging the roots of trees and shrubs.
Protect Pollinators
- Apply in the early morning or evening when bees are less active.
- Kill weeds before they flower. Avoid spraying flowering plants.
- Do not spray on bees or insects.
Avoid Wet, Windy, or Hot Weather
Use during favorable weather for best results.
- Don’t spray when it’s raining or when rain is expected in the next 24 hours.
- Wind causes spray to drift that can get on you and desired plants.
- Herbicides may be less effective in hot weather if the target plants are moisture-stressed.
- Some herbicides can turn into a vapor in hot weather and damage nearby plants.
Don’t Spray into Water
- It’s illegal to apply herbicides in a stream or slow moving/wetland pool.
- You need a product registered for aquatic areas. This includes waterways, ditches, drains, and other places where water collects.
Storage & Disposal
- Store in a secure area away from children.
- Don’t put unused herbicide products in the trash.
- Never pour down any drain or waterway.
- Take unused herbicides to a hazardous waste facility.
Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of herbicides.
For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website
More about:
About Using Pesticides on School Grounds in Oregon
If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).
NEED HELP?
The National Pesticide Information Center (NPIC) can answer questions about pest control chemicals.
1-800-858-7378 or npic@ace.orst.edu
Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.
Content provided by editor Weston Miller and writer J. Jeremiah Mann. Pesticide safety information edited by Kaci Buhl.
Peer review facilitated by OSU Department of Horticulture.
POISON OAK REFERENCES
How to Manage Pests Pests in Gardens and Landscapes: Poison Oak
University of California IPM
Pacific poison-oak (Toxicodendron diversilobum)
University of California IPM
Weeds: Poison ivy and Poison oak – Toxicodendron spp. (Rhus spp.)
Washington State University Hortsense
How to remove poison oak plants and treat a rash
Oregon State University Extension Service