By James Matthews
Local Journalism Initiative Reporter

Giant Hogweed is an invasive plant harmful to people, and there are five patches of it in Dysart et al.

Dr. Adam Gorgolewski, the research coordinator at Haliburton Forest and Wild Life Reserve Ltd. (HFWLR), told town council during its regular meeting Nov. 22 that some of the plants on Fishtail Lake Road have reached as high as 15 feet tall. They can grow as high as 20 feet.

The patches are growing quickly and primarily exist on land owned by the Dysart et al municipality. To a lesser extent, it is on land owned by HFWLR and a privately-owned cottage property.

Patches of Giant Hogweed have been found along Fishtail Lake Road and an adjacent snowmobile trail. There are smaller patches in the range of 10-50 plants, two medium-sized patches of 50-100 plants, and two larger patches that each contain well over 1,000 plants each. 

Gorgolewski presented town council a proposal for a co-operative plan and cost-sharing agreement to eradicate the Giant Hogweed, whereby the reserve would pay $5,000 of eradication costs, the private landowner would contribute $200, and the municipality would pay the remainder estimated to be as much as $49,800.

Gorgolewski wrote in a report to council that it is in the best interest of all parties to eradicate the patches of Giant Hogweed.

“If we each act individually, our efforts may not be in sync and may not be as efficient,” he wrote. “Therefore, we propose to move forward with a cooperative treatment plan.”

HFWR would also conduct monitoring and manual removal of additional plants after the initial eradication effort has concluded, at its own expense. 

Gorgolewski said eradicating the patches of Giant Hogweed will require a multi-year approach.

The benefit of this kind of situation is the herbicide wouldn’t have to be sprayed across the whole affected area.

“They would be targeting the specific hogweed plants,” he said. “It wouldn’t come into contact with any plants other than the Giant Hogweed.”

Gorgolewski said spraying would need to be carried out in late spring. It will require three to five years of herbicide applications. The areas will have to be monitored for some time afterwards to ensure no subsequent plants sprout, he said.

“If they did, we could remove those manually rather than using a herbicide,” Gorgolewski said. “But, with this amount of plants, the only real way of tackling it is to use a herbicide.”

Giant Hogweed is a perennial plant that has been present in Ontario since 1949. It was most likely introduced from ornamental gardens, and now occurs in isolated patches throughout south and central Ontario. 

The plants produce seeds three years after germinating, and each plant produces an average of 10,000 seeds per year. Seeds are spread via wind and water. Humans can also move seeds unintentionally on vehicles or when soil or mulch is transported.

Seeds usually sprout the following year, but can remain dormant in soil for up to three years. Giant Hogweed is able to establish in low-nutrient soils, but also requires direct sunlight to thrive.

These factors cause Giant Hogweed to readily establish along the sides of roads and trails. Once established, it tends to crowd-out native plants and reduce biodiversity.

Dysart Mayor Murray Fearrey said the weed isn’t new to Ontario or Haliburton County.

“If you touch this plant, are you infected then or not?” the mayor said.

Gorgolewski said that’s the case. The stem and leaves have little irritable hairs on them. Inside those hairs is a sap that transfers to people and animals.

“If sunlight hits that sap, then the burns will occur,” Gorgolewski said.

Fearrey said the hogweed was tackled on Fishtail Lake Road from 2017 to 2019. A troublesome aspect of that work then was they could only treat the road allowances but couldn’t access nearby private property.

Gorgolewski said he’s spoken to landowners that have the hogweed and they’re in favour of removing the troublesome plants.

He said the plants, after cutting, would be tied up in garbage bags and left in the sun for a number of days. The time basically cooking in the sun inside the bags kills the Giant Hogweeds.

“You can leave them on-site,” Gorgolewski said.

Fearrey said council should research the issue more and then defer the debate until they get to work setting spending priorities for the 2023 municipal budget.

“I’m not saying they’re not there, because they are,” Fearrey said. “And somebody has to deal with them. We just need to figure out the best way and who pays what?”