Naturalization of Vacant or Maintained Areas

Naturalization of vacant or maintained areas in urban and periurban communities occurs when certain maintenance practices (i.e., mowing) ceases and native trees, shrubs and other plants are reintroduced to the land.

Recommended Practices

Stop mowing. While allowing natural grasses to grow and become established, municipalities should still control noxious weeds and keep the area free from refuse.

Plant native trees and shrubs. Native species are planted after grasses are established. It is recommended that a variety of native species be planted to ensure a biodiverse ecosystem in the naturalized area.

Enhance habitat. Once trees and shrubs have established, naturalization may entail planting the understory with native shrubs and wildflowers to increase biodiversity and encourage wildlife to use the naturalized area as habitat.

Project Considerations

Naturalization initiatives may take a long time. Municipalities and developers undertaking this example of NBS should begin by assessing the initial state of the property i.e., are there noxious weeds on site that need to be controlled, what other species of plants are currently in place, etc. Weeds and undesirable vegetation must first be removed from the property. Naturalized grasses and other species may take years to become established before larger trees can be incorporated.

Public consultation, awareness and education is important for naturalization projects to succeed. The naturalization process takes time and residents may have concerns that the area looks untidy after mowing ceases and before the area is fully naturalized.

The Business Side

By ceasing mowing and maintenance of grass, municipalities can save money through naturalization. Weed control in the first stage of the process needs to be budgeted for; however, once the area is naturalized, maintenance costs decrease significantly. Planted trees, shrubs and forbs in the naturalized area help to absorb rainwater and therefore reduce the risk of flooding by decreasing stormwater runoff. Plants also help to filter water and improve quality. Vegetation in these areas also sequester carbon from the atmosphere, provide shade and reduce the urban heat island effect. If native fruit-bearing trees and shrubs are included in this type of NBS, they can provide food for the local community.

The Nature Side

Because naturalization utilizes native plant species, they help to provide habitat for birds, pollinators and other wildlife and increase local biodiversity. When naturalization is successful, the resulting healthy ecosystems provide an abundance of ecosystem services, including improving air quality and sequestering greenhouse gases, filtering and slowing the flow of stormwater across the landscape, producing oxygen, providing windbreaks to capture drifting snow and dust, reducing the urban heat island effect and providing shade, stabilizing slopes in riparian areas and preventing erosion. Because naturalized areas are no longer mowed, this reduces greenhouse gas emissions from mowing equipment.

The Community Side

As naturalization initiatives progress, they become increasingly aesthetically pleasing to residents and community members. These areas can provide new or additional green space for recreational activities and the increased availability of nature in a community or neighbourhood also has positive effects on mental and physical health. Citizens may become engaged in environmental initiatives during the process of naturalization and in stewarding the new natural area as it matures. As trees grow, they provide additional shade and reduce noise levels especially when plantings are done near roadways. Added greenspace and trees increases property values in adjacent neighbourhoods.

Aguilar Rojas, J. 2016. Urban Naturalization for Green Spaces in the City of Edmonton, Alberta, Canada. Thesis. University of Alberta.

City of Edmonton. 2021. Naturalization. City of Edmonton.