Weeding out invaders

A program at Camden State Park taught about invasive garlic mustard, and how to fight it

Photo by Deb Gau Joe Gartner reached down to find small garlic mustard plants near a trail at Camden State Park on Monday. Gartner was giving a talk on how to ID and remove the invasive plants.

CAMDEN STATE PARK — The forest floor near the south picnic area at Camden State Park was looking like it should, Joe Gartner said.

“This is beautiful,” Gartner said as he led a small group of people along a park trail.

But among the leaf litter and woodland plants like Dutchman’s breeches and violets, Gartner could still find some unwelcome visitors. He bent down to point out a cluster of plants with round, scalloped leaves. These were his target — garlic mustard.

Garlic mustard is a plant in the mustard family, Gartner said, and it does smell like garlic when its leaves are crushed.

“At this time of year, the key thing is it gets little four-petaled white flowers. The other thing you can do is smell it,” Gartner said.

Garlic mustard is also invasive, spreading quickly and crowding out native Minnesota plants. Gartner, a New Ulm resident and a retired science teacher, has been spreading the word about garlic mustard around the state. On Monday, he was at Camden State Park giving talks on how to identify the plants, and remove them before they spread.

“We need to have more people know about this stuff,” Gartner said.

Garlic mustard can thrive in forests or other shady areas.

“I’ve had people that have it in farm groves,” Gartner said. “It likes alkaline soil and deciduous woods.”

If the plants get established, they can not only crowd out native plants, but they can degrade the landscape, he said. Garlic mustard plants produce a chemical that makes it hard for native plants and trees to grow back, he said.

Gartner said he likes to take the approach of identifying garlic mustard plants early, and acting quickly to remove them.

“If you pull it when you only have a few plants, it’s easier to get under control,” he said.

Garlic mustard plants have a couple of different looks. The plants take two years to grow and flower, Gartner said. First year plants grow low to the ground, with rounded leaves. Second year plants grow stalks two to four feet tall, with small white flowers.

Gartner said he looks for garlic mustard plants in spring — partly because that’s when the plants are flowering and easier to identify, and partly because it’s before the plants have a chance to develop seed pods. Garlic mustard seeds can be spread by deer, by shoes, and by mowing, he said.

As part of his talk, Gartner took area residents on a short trail hike and demonstrated how to gently pull up smaller garlic mustard plants. He recommended using a dandelion digger or a small trowel to loosen — but not dig up — the dirt around the plant stalk if it doesn’t come up easily.

When you pull garlic mustard plants, Gartner said, it’s important not to compost the plants. They could still grow or spread seeds that way. He recommended putting the plants into trash bags instead. You should also be careful to clean off your shoes to prevent spreading seeds, he said.

While it’s not a problem to remove garlic mustard from your own property, Gartner cautioned that the rules are different when it comes to plants growing in public and state parks. You should only remove plants from parks with permission, he said. If you see garlic mustard growing in a park, you should always contact park staff to let them know about the plants, and where they’re located, he said.

More information and resources on controlling garlic mustard can be found online, Gartner said. He recommended the Iowa Department of Natural Resources’ website. Gartner’s own website, thegarlicmustardman.com, has links to other information as well.