removing poison oak safely

Asked November 24, 2018, 3:40 PM EST

I have 3 acres of land with a lot of poison oak and I'm very sensitive to it. All last summer I periodically donned a disposable bunny suit and tried to carefully spray roundup on the poison oak while trying to avoid all the native plants. I reduced the poison oak a little bit. Now that the soil is wet I would like to dig up some of the poison oak to further reduce it. My question is whether you have any advice as to what to do with the plants and roots after removing them. If I leave them in a pile to rot, will the urushiol eventually break down? How long might that take? I've been told to bag it up and haul it to the dump, but I hate to add all that plastic to the dump.

Lane County Oregon

1 Response

Sounds like you're taking some good first steps towards getting rid of the poison oak at your site.

I wasn't able to find any research that clarified whether or not any composting process can break down uruishiols. Quoting another Expert on poison ivy (which also has uruishiols):

"Eradicating poison ivy can be a real challenge, especially for people who are allergic or highly sensitive. I did some research and was unable to find anything definitive about the degree to which composting would break down the oily toxin in poison ivy (urushiol). Some are of the opinion, and I agree, that it would be more likely to break down completely in a large-scale commercial composting operation than in a home compost pile. Most home compost piles do not achieve the consistently high temperatures that commercial operations do, nor do they get same degree of turning, mixing, aeration, and so on, that accelerate decomposition. Do you know whether your county or region has a commercial composting facility?"

You could contact your local disposal service and ask if poison oak is allowed to be composted there. Since they often deliver this compost to home gardeners, they are probably quite aware if/when their process does not break down the itch-inducing compounds.

In the event that your local recycler won't compost poison oak, I would not risk composting it at home.

It sounds like you're on the right track. Check out this newly updated OSU Extension resource on managing poison oak for additional tips and cautions: https://catalog.extension.oregonstate.edu/pnw108/html

I'd suggest strongly considering the cut stump method described in this document. You can reduce your contact with the plant and overall exposure by leaving the roots in the ground and just spraying the cut stump with an appropriate herbicide to kill the root, which can decompose in place. There will be less bagged material to dispose of.

If you need to treat leaves of poison oak that may resprout in future, and if you and have grass at the site, I'd suggest a broadleaf herbicide instead of glyphosate/RoundUp. This will leave the grass alive and create more competition for any resprouting poison oak and other weeds that might take over a totally bare patch of soil.

Good luck and thanks for contacting Ask an Expert.