Garlic mustard also fights dirty by waging what Hamilton Conservation Authority operations manager Bruce Mackenzie calls “chemical warfare” to ward off other plants.

The invasive species has quickly become the new local scourge as it carpets forest floors and conservation areas, pushing out wildflowers like trillium and dogtooth violets, including by releasing a chemical into the soil that inhibits their growth.

Mr. Mackenzie is hoping a pilot project at the Eramosa Karst will help find a natural way to halt the pesky plant’s seemingly unstoppable march across the city’s newest conservation area.

He said he’s worried garlic mustard will not just affect wildflowers, but dependent bugs and the moisture, bacteria and fungus in the soil.

“It’s my fear that it will make the gypsy moth look like a holiday,” Mr. Mackenzie said, referring to the leaf-devouring caterpillars that required aerial spraying last spring.

“It’s just exploded this year. If you hadn’t come here for three years, it would be very hard to fathom how this thing has come in so quickly,” he says.

“The chemical it releases into the soil, what life forms does it affect? Does it affect other tree species or does it affect the microscopic animals?”

Working with the Friends of the Eramosa Karst, the conservation authority has created two test plots to gauge potential strategies for controlling the plant, whose prolific seeds can remain dormant up to seven years.

One 25-square-metre plot will use landscape fabric and chip cover to eliminate the garlic mustard by essentially smothering it, while another will have FOTEK volunteers pull the candle-shaped plants, which have green leaves and tiny white flowers.

A nearby third plot has been set up in an area where there is almost no garlic mustard to see if it spreads there.

“I’m surprised by the height of it this year. Last year it seemed to be a little bit lower, but (now) it’s so dense,” said FOTEK volunteer Rita Giulietti, who is thankful the plants are at least easy to pull out.

“Ironically, it’s kind of pretty, but as you can see it’s crowded out all of these native plants,” she said of the handful of trillium and others that managed to survive in the group’s test plot. “You’ve really got to dig through the garlic mustard to find the stuff that’s supposed to be here.”

Mr. Mackenzie said among the mysteries of garlic mustard is how it spreads so quickly given that its little black seeds aren’t dispersed by wind.

“Once one plant gets established, it can generate several hundred seeds, so it’s not hard to figure out how it makes a colony in a hurry” he said. “But how these individual seeds get moved around, whether it’s mud on a person’s foot or a deer’s foot, there’s many different ways the seed can be transported.”

Other than two types of moth larvae, garlic mustard has no natural predators.

Deer and rabbits won’t even try a nibble because of the smell, while other insects also take a pass. Among wildflowers, the Canada may-apple is one of the few successful holdouts.

That’s made the non-native plant, which flowers in the second year of a two-year lifespan, ubiquitous in other areas like the Dundas Valley, Iroquois Heights and Royal Botanical Gardens lands.

Mr. Mackenzie acknowledged it will take more than human intervention to turn back the advance.

“For the conservation area, with our thousands of acres, there’s no end in sight until nature sort of decides this plant has eaten itself out of house and home or some kind of disease or insect comes along to control this plant.”