I am dealing with poison oak growing in a stand of trees: Douglas firs, big-leaf maple saplings, and others. I have tried manual control and was unsuccessful. What would be the safest topical herbicide to apply to the leaves and stems while minimizing damage to the surrounding trees?
The most effective and affordable products over time will be those containing glyphosate and triclopyr.
Application methods
You asked about a contact herbicide, and glyphosate fits the bill. Be aware that glyphosate is non-selective and can harm your other plants. Here are some application methods that you might want to try:
- Apply with a brush: I recommend using a paintbrush or something similar to keep the product on target
- Wicking: For this method, dangle a wetted wick to come in contact with the target plants.
Consider a fall campaign for long-term control. In the waning days of fall, plants transport sugars from the shoots to the roots, and glyphosate can travel easier to the roots by going with the flow.
For more information about application timing, read the OSU Extension publication Pacific Poison-oak and Western Poison-ivy: Identification and Management.
Safety precautions
Here are some important safety tips when managing poison oak:
- Limit skin contact with poison oak. Wear vinyl gloves and other protective clothing, because the oils can seep through permeable materials
- Avoid cross-contaminating your other clothing and linens. Wash contaminated clothing items separately with soap and water.
I wish you good luck!
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Use pesticides safely!
- Wear protective clothing and safety devices as recommended on the label. Bathe or shower after each use.
- Read the pesticide label—even if you’ve used the pesticide before. Follow closely the instructions on the label (and any other directions you have).
- Be cautious when you apply pesticides. Know your legal responsibility as a pesticide applicator. You may be liable for injury or damage resulting from pesticide use.
