Update on Invasive Species Control at Malden Park

The City of Windsor is taking a proactive approach to ecological health at Malden Park (4200 Malden Road) by launching a coordinated effort to manage invasive species. Visitors may encounter a series of similar cut marks on approximately 50 trees in the park and are advised not to be alarmed. This is part of a coordinated marking/girdling of invasive species (tree-of-heaven) and can be mistaken for vandalism. Please be assured that girdling is necessary at this stage of the year to inhibit the spread of seeds. 

Controlling invasive species is important because native species take time to establish, typically more than nearby invasive species. If invasive species like tree-of-heaven are not controlled, they threaten the success of habitat restoration efforts currently underway in this area of park. The City of Windsor hired a contractor to implement control measures on phragmites and wild parsnip in fall 2025, and tree-of-heaven control occurred over this past winter. 

Parks staff will monitor the area during this year’s growing season and follow up as required; these species generally take 2 to 3 years to completely remove. In the years following successful control, the Parks Department will be planting native trees and ensuring native grasses and wildflowers are established. 

Part of the monitoring program will include checks of the adult tree-of-heaven specimens that were treated and left standing. These trees can stand dead for years, providing habitat for birds, insects, and other species that rely on snags for foraging and nesting, while ceasing to be a threat to nearby habitat. If they become a potential safety concern to visitors due to damage or deterioration, they will be removed. 

About the Invasive Tree-of-Heaven

Tree-of-heaven is not a direct threat to human health, but it is a significant threat to native species and an indirect threat to the local fruit and wine industry because this tree is the preferred host of the spotted lanternfly, which is currently high on the Canadian Food Inspection Agency (CFIA) watch list.