Wednesday, June 25, 2014

In Hamilton County, A Giant Hogweed Alert

Giant hogweed has white, umbrella-shaped flowers.  Photo courtesy of the Adirondack Park Invasive Plant Program.  It was a hot August day and Lenny and I had the truck windows rolled down as we hunted for a home address in Speculator. We were following up on the identification of a poisonous invasive plant.

“I bet it’s cow parsnip,” said Lenny.

“That’s the house number. Turn here,” I pointed.

I hopped out and gaped at the plant. It towered above my height of 5 feet 9 inches. The leaves were enormous. I walked up to take a closer look saw hairy stems blotched with purple.

“It’s giant hogweed,” frowned Lenny.

Back at the office, Lenny and I contacted the Adirondack Park Invasive Plant Program and the New York State Department of Environmental Conservation and requested their help to manage the small stand of giant hogweed.

“Being the first documented occurrence of giant hogweed in Hamilton County, rapid response was critical to ensure that this site in Speculator was not allowed to spread to new areas,” explained Brendan Quirion, APIPP’s Terrestrial Invasive Species Project Coordinator. “This site was also located in close proximity to a dwelling posing an imminent threat to human health.”

This invasive plant is a public health hazard because its sap reacts with sunlight and moisture (sweat) and can cause blisters, burns, scaring, or blindness. Children pretend hollow stems are flutes, swords, or telescopes, and may be harmed by the sap. People may encounter sap if they brush up against broken vegetation.

A native to Eurasia, giant hogweed arrived in the United States as an impressive ornamental that was a coveted addition to gardens and arboretum due to its large size and beautiful flowers. Plants escaped their confines and giant hogweed is now established throughout the northeastern United States and beyond.

Due to giant hogweed’s gargantuan size, it can out-compete native plants for sunlight and growing space. Wildlife may lose a food source. Shallow roots are not as affective at holding soil in place as native plant roots, and soil erosion may occur.

 A few key characteristics can help with identification as this invader can be mistaken for cow parsnip, poison hemlock, or angelica. Hairy, green stems have purple blotches. Small white flowers grow in clusters shaped like an umbrella that can span 2.5 feet. Flowers bloom in June or July. Leaves are lobed and large, often reaching 5 feet.

Strong agency partnerships allowed for rapid response to the small stand of giant hogweed growing on private property in the Village of Speculator, Hamilton County. The property owners had been cutting the invader for years, only to see it grow back larger than before. They contacted the DEC’s giant hogweed hotline, and the site location was passed on to APIPP.

Lenny and I asked the landowners to sign an indemnity agreement to permit herbicide treatment on their property, and also gave them an invasive plant information packet. Two weeks after the paperwork was signed, certified APIPP staff removed the flower heads then sprayed the plants with herbicide. These coordinated efforts and public awareness highlight early detection and rapid response at its very best.

In an effort to get the word out about the adverse impacts of giant hogweed, I made a movie, ‘Giant Hogweed: a Toxic Invader’ that can be viewed on You Tube.

While searching for photos to include in the movie, I was fortunate to come across Hannah Marie Schmale’s photography blog. The photos she posted showed her bottom lip swollen and blistered from a reaction to giant hogweed. I was interested in her story and she eagerly shared it with me.

“July of 2011 I participated in the Seattle to Portland Bikeride,” detailed Schmale. “The route was mainly roads, and parts of it were on paths. There were designated rest stops throughout the ride, but I, of course, could not wait! Several times throughout the 2 day ride, I decided to use the restroom in the bushes! I specifically remember parting the bushes as I walked into them. Each time, before I started riding again, I applied chap stick with my finger. I was only putting it on to moisturize my lips – I was not even thinking about the fact that there was no SPF in the chap stick I was using. I would apply it onto my bottom lip and then press my lips together. The helmet I was wearing had a built in sun visor. So I believe that what happened was I came into contact with the giant hogweed plant when I was parting the bushes, then my contaminated finger transferred the toxin directly to my bottom lip, and then the shiny chap stick attracted the sun even more while I was riding in the direct sunlight for 2 full days. I think my upper lip didn’t get much of the toxin, and was possibly shaded by my visor.”

The sap of giant hogweed can react with sunlight and moisture to cause blisters and burns.  Photo courtesy of Hannah Marie Schmale.  Schmale’s reaction looked terrible in the photos. “The pain was definitely not the worst pain I have felt in my life,” she explained. “Maybe a 5 out of 10. It was mainly just really uncomfortable because it was so tight and there was lots of pressure. The swelling went away in about 3 days. Then the skin turned into a black scab, and then about a week after the initial swelling, the scab started peeling off, revealing fresh brand new lip underneath! It has been normal ever since.”

Invasive plants are persistent and management efforts may take years before complete eradication is seen. The infestation in the Village of Speculator is on our radar and will be checked during the upcoming summer months for re-growth. Any stragglers will be treated with herbicide.

If you think you spot giant hogweed, do not touch the plant. Contact APIPP (518-576-2082), the NYS DEC (1-845-256-3111), or the HCSWCD (518-548-3991, for assistance.


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Caitlin Stewart manages the Hamilton County Soil and Water Conservation District. The District's mission is to manage and promote the wise use of Natural Resources in Hamilton County. Caitlin will be sharing the District's conservation-focused services, programs, and events. She’s been a full time resident of Hamilton County since 2008 and is an avid hiker, skier, paddler, and biker. She is obsessed with adventuring with her dog Artemis.

7 Responses

  1. Judy says:

    If I understand it correctly, the “herbicide” you are using is glyphosate. I am appalled that this would be used in the Adirondack Park. Recent reports and studies indicate that while this product is effective in the short run, it only produces larger and more persistent weeds than it killed in the first place. It is also toxic to humans. It does not remain where it is applied but enters the soil and the aquifer. While many reports of Roundup’s harmful, long term effects are anecdotal, the evidence is building quickly. Many entities including entire countries are banning it’s use. See FB page US Comprehensive Glyphosate ban treaty page. This is not the answer to invasives in the Park. We need to examine this approach and determine if we want to contaminate our land, water and selves.

    • Paul says:

      Judy, Glyphosate is not toxic to humans. It is a far better herbicide than some of the other alternatives as far as its impact on the environment. It breaks down very quickly in the soil. Should it be used to control invasives in the Adirondacks? I have no idea.

        • Paul says:

          This is looking at concentrations (and mixtures with other compounds) that is far greater than any concentration used for herbicidal applications. If you drink enough water it will kill you. If you look at the conclusions for the paper it really shows that it is safe if used properly. This product has been shown to be safe and it is backed up by years of use in the field. If it were toxic at recommended levels we would all be in trouble.

          In this particular case, if you need a herbicide (and like I said maybe not here) you have to pick the one that is the safest. This is a pretty good choice. Better than using one that persists in the environment and causes lots of other negative consequences.

          From the paper:

          “Most reported cases have followed the deliberate ingestion of the concentrated formulation of Roundup (The use of trade names is for product identification purposes only and does not imply endorsement.) (41% glyphosate as the IPA salt and 15% POEA).”

    • Paul says:

      They might also be using something like 2-4-D. For this you want a good broad-leaf herbicide. Best to use something that won’t have much impact on the native grasses. Nobody want to spay this stuff if you don’t need it but getting rid of this plant is a top priority.

  2. Pete Klein says:

    Keep up the good work, Caitlin.

  3. Wally says:

    Thanks for the article. I think these plants should be removed by the best available means, inside or outside the park.

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