The Gillson Park Lesser Celandine Project

A Strategic Approach to an Invasive Challenge

Gillson Park is bustling with activity, not just with park-goers but also with our Parks Department team tackling one of nature’s tough contenders: Lesser Celandine (Ficaria verna). This invasive species has been steadily gaining ground in our region, and you may spot our staff scouting, applying treatments, or testing innovative propane flaming methods to manage its spread.

The Challenge: Lesser Celandine

Lesser Celandine is native to Europe and western Asia. It was introduced to the United States as an ornamental plant in the 1800s. It first appeared in Illinois in the 1970s and has gradually entered Wilmette’s parks over the last decade.

This early-blooming spring ephemeral produces heart-shaped glossy leaves and eye-catching yellow flowers. While seemingly harmless, it spreads aggressively via tubers and bulbils, forming dense mats that overshadow native plants and turfgrass. Removing Lesser Celandine is no small feat—every bit of its above- and below-ground structure must be eliminated, as even a single leftover tuber can sprout a new colony.

In recent years, Lesser Celandine populations in Gillson Park have increased dramatically, prompting us to take a more structured approach to managing their growth.

A Systematic Solution

Enter the 2024–2026 Lesser Celandine Management Plan. Wilmette Park District teamed up with expert organizations, including the IPM Institute, Natural Communities, Good Nature Organic Lawncare, and Midwest Grows Green. In late 2023, after months of site visits, brainstorming, and collaboration, our plan was set.

In February 2024, Parks and Planning staff began scouting Gillson Park, mapping and flagging populations of Lesser Celandine. This effort ensured a clear view of its spread during its brief window above ground. Once the plant began to leaf out, we trialed several treatment methods:

1. Synthetic Herbicides (Rodeo)
2. Organic Herbicides (Finalsan)
3. Propane Flaming Treatments

Given Gillson Park’s high visibility, historical significance, and proximity to Lake Michigan, Wilmette Park District took steps to balance effectiveness and environmental responsibility.

Progress and Future Steps

We are just one year into this three-year journey, and while full results won’t be immediate, the groundwork already completed will lead to success. Beyond chemical treatments, our plan emphasizes long-term strategies, including cultural controls and introducing native plants to reclaim affected areas.

This past year, we’ve grown more knowledgeable about the plant and the effectiveness of various control measures. While Lesser Celandine remains a formidable adversary, we’re confident that persistence and innovation will help us turn the tide.

Stay tuned for updates as we continue this vital work, protecting Gillson Park’s natural beauty and ecological balance.

Learn More

1. Midwest Grows Green: Our Backyard War
2. Ohio State University Extension: Understanding Lesser Celandine
3. University of Illinois Extension Newsletter