Safety Warning: Beware of Blue Dye

Oxbow Regional Park


In the Portland area, a regional government called Metro is in charge of managing some 14,000 acres of wilderness, including Oxbow Regional Park, Smith and Bybee Wetlands, Mount Talbert, and a number of other newly acquired parks that are not yet open to the public. When I heard that Metro uses herbicides in its parks, I became concerned about the safety risks to foragers and herbalists who may be wildcrafting unawares.

I called Dan Moeller, the Natural Areas Land Manager at Metro, who is responsible for overseeing management of invasive species, including herbicides. He told me that Metro sprays in the spring and the fall, and that when it does, employees post signs, staked into the ground, at the entrance points to the wilderness areas. “We post all areas that have herbicide applications for the period of time that the chemical is active and toxic to humans,” Dan said.

They also use a blue dye to stain the plants. He said targeted species include holly, ivy, knotweed, clematis, tansy ragwort, Himalayan blackberry, garlic mustard, scot’s broom and hawthorn. Generally, he said, the plants will wilt very quickly, so in addition to a blue tinge you would see that they look unwell.

Explaining the method of application, Dan told me, “We don’t spray a tree of hawthorn. We would cut it off at the stump and then, with a sponge, dab directly onto the stump.”

The chemical Metro uses most is glyphosate. That is the most widely used pesticide in America, and one of the ingredients in Monsanto’s Round-Up. Metro also uses triclopyr. Both are considered low-toxicity compared to other chemicals, and in some reports are said never to have resulted in human hospitalization due to exposure.

“All the chemicals we use have been approved by Salmon Safe and heavily vetted by different agencies to make sure there’s no effect on fisheries and water systems,” Dan said. “For the most part, if these chemicals are applied and they’re dry, they come to the point where you would have to ingest an insane amount of it to get sick.”

I’ll continue to learn more about these chemicals, and I encourage you to do the same.

Of course, harvesting wild plants is technically not allowed in Metro parks without an expensive permit ($105), unless you’re taking small quantities of berries or nuts. That said, Dan said he encourages anyone who wants to take out invasives by hand to call him and talk, at (503) 797-1545.

Please share this information with anyone who harvests wild plants in the Portland Metro area.

8 thoughts on “Safety Warning: Beware of Blue Dye

  1. I used to take my dog with me on some of the trails in Forest Park. However, I noticed that after walking him- and a few days after- his breathing was not right and there was as certain amount of wheezing. The walks occurred in the winter-so pollen is unlikely to be an issue. .

    He has no issue on the Columbia Gorge trails and no allergies that I am aware of. Again, he is a high endurance dog and only seems to develop this issue when on these trails.

    The warning signs that are alluded to above either are not consistently applied or are allowed to remain for months- making it difficult to determine when the herbicides were actually applied.

    I fully agree with the Patrick Jones and I do not buy the argument that the city makes- that the herbicides are applied infrequently and in low amounts- or that the level of ground water contamination is acceptable.

  2. Pingback: How Hawthorn Healed My Dog « First Ways

  3. check out the film ‘the world according to monsanto’. there’s so much out now on glysophate. read ‘slow death by rubber duck’. pesticides are linked to animal miscarriages, parkinson’s disease, adhd, alzheimer’s disease, cancer, and many other things. then there’s the reduced fertility in the soil problem – soils become deserts. in an era of climate change that’s pretty bad, right? then there’s the mega problem of glysophate being energy intensive – pretty troubling in an era of peak oil when our food system is so reliant on it. canada is banning glysophate throughout their country as they unpack what’s really behind the science. the japanese refuse to allow roundup ready crops into their country until a generation of american people, who have been eating frankenstein food, are studied – sensible, they have their government looking out for them. the only science being studied concerning pesticides in the usa is being conducted by the chemical companies, which is what i call shareholder science… pretty alarming, especially as the usa government has been infiltrated by ex monsanto execs. and so private farmlands and the public (private?) commons are poisoned, helped along by fanatical ecologists and land management bureaucrats who see environments as static. glysophate kills bees, major contributors to our food systems. the list goes on and on. pretty sad stuff.

  4. I believe Dan said he has a staff of four people for the 1,400 acres…that might be part of it. I think he said they do replant native species at times as well.

  5. The thing with this spray stuff (I’ve seen them walk around with their hoses of blue herbicides in Washington too) is that it kills the invasive plants, but, to my knowledge, nothing is planted in their place. Meaning, all this upturned soil is once again ready to be colonized by invasives. So I wonder if this technique wouldn’t be more effective if new, native plants were planted in their place to protect the soils? After all, many invasive plants serve an important ecological role as well….

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