CONESTOGA, Pa. (WHTM) — Shenks Ferry Wildflower Preserve in Lancaster County is renowned for its spring wildflowers. While the wildflowers sprout on their own each year, the Lancaster Conservancy and its volunteers work to manage invasive species and prevent them from impacting the growth of the beloved spring ephemerals.

On a brisk Saturday morning in late March, about 15 volunteers gathered at Shenks Ferry to pull invasive garlic mustard plants.

“Garlic mustard is a biennial plant, which means it’ll last for about two years, and then it’s a prolific seeder, and so it can really easily take over a piece of land if it’s not controlled,” explained Keith Williams, community engagement coordinator for the Lancaster Conservancy.

Volunteers plucked garlic mustard from along the paths and carefully picked their way up a hill, gathering about 250 gallons of the invasive plant in just a few hours.

“It’s a surgical removal,” said Williams. “The garlic mustard is coming up at the same time that the spring ephemerals are coming up, so we really stand a chance of doing as much damage by trying to do the removal of the garlic mustard as if we would just leave it in place.”

It’s a bit of a Catch-22 — they can remove the garlic mustard but risk trampling the species they’re trying to protect, or they can leave the garlic mustard but risk it spreading rampantly and outcompeting the spring ephemerals.

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“These spring ephemerals can be 20 years old, and this is their only chance to make sugar, make carbohydrates, and reproduce out of the rest of the year. The rest of the year they’re essentially dormant,” Williams explained, “and so if we were to step on that plant and inadvertently snap that stem, there’s a good chance that 20-year-old individual plant’s going to die now.”

This is why visitors are not allowed to walk off the paths at the nature preserve, and it’s why the volunteers who leave the trails to pull weeds are taught how to do so very carefully, intentionally placing their feet to not harm the wildflowers.

Plants or other species that aren’t native to an area are more prone to dominate that area, Williams explained, because they don’t have natural predators or other factors that help control the populations of native species.

Garlic mustard is invasive in Pennsylvania — Penn State Extension says it was brought to the U.S. by European colonizers and first documented in New York in the late 1800s — but not all non-native species necessarily end up being invasive.

Non-native species exist in an area from which they did not originate, Williams explained. Among non-native species, there are naturalized organisms that assimilate into the ecology of their new location without taking over the ecosystem, and then there are invasive species, which are non-native species that dominate their new location without natural population controls to keep their numbers in check.

Some of the invasive and non-native species around Shenks Ferry are “landscape escapees” that were brought to the area intentionally for landscaping and then moved to other locations through natural processes. Others were brought to the area to serve a conservation purpose, like preventing erosion, but then had unforeseen impacts, Williams explained.

Williams said the careful work of volunteers pulling garlic mustard last year paid off. They pulled about 700 gallons of the plant from Shenks Ferry and other preserves managed by the Lancaster Conservancy. In the Shenks Ferry preserve, Williams observed lasting impacts of their efforts, with the side of a hill that was covered in garlic mustard last year cleared of the plant this season.

Volunteers returned to Shenk Ferry for a second day of garlic mustard pulling in April, but Williams said the work of managing invasive species is ongoing throughout the year and among multiple preserves. Individuals can volunteer with the Lancaster Conservancy to help, Williams said, or they can take steps at home like landscaping with native species to mitigate the spread of non-native and invasive plants.

Of course, all of this work is to ensure that the spring ephemeral wildflowers at Shenks Ferry are able to continue thriving. The wildflowers typically reach peak color around Easter, Williams said, but visitors can also see some unique plants before and after that.

Williams reminds those visiting Shenks Ferry to stay on the designated trails and leave no trace to protect the wildlife on the preserve. Learn more about visiting Shenks Ferry here.