FAQs

In 2016, the Public Works Department hired several interns from the University of Missouri to conduct a cost-benefit analysis to determine if the City would incur additional costs or save money if it was to stop mowing grass and convert roadside vegetation to native habitat. The results of this analysis showed that the annual cost of mowing grass is more expensive than installing and maintaining native vegetation. These values vary with precipitation, fuel costs, vehicle replacement/maintenance, etc., but our best estimate shows that mowing 88 acres of grass costs approximately $230,000 to $350,000 per year. As we convert the majority of the 88 acres into native wildflower plantings, the cost of maintaining our roadside vegetation drops to approximately $70,000 per year, resulting in a cost savings of $160,000 to $280,000 per year. This figure does not include the initial installment cost, approximately $210,000 over a three-year period.

The City of Columbia hired an ecological services consultant to prepare selected roadsides, medians and roundabouts, who prepared the first roadside pollinator sites in late spring 2019 using chemical and mechanical techniques, including the controlled use of herbicide, mowing, and where appropriate, prescribed fire. From November 2019 to the end of January 2020, the consultant broadcast seeds across the prepared sites with a short (less than 3 feet tall) native wildflower seed mix. In spring and summer 2020, the consultant spot-sprayed for encroaching invasive plants. The consultant also mowed the new planting with a blade set to six inches away from the ground in order to prevent tall weeds from shading the new native seedlings.

Roadside pollinator habitat will result in some mortality of flying and crawling insects. However, studies show that this mortality does not always add to the decline in population numbers.

Ecosystem Benefits to the City

Ecosystem services are the numerous and varied benefits that people freely gain from the natural environment and from properly-functioning ecosystems (Figure 2). Wetlands provide flood control and erosion services. Urban forests provide shade which cools city space. These ecosystems and the many other systems that exist provide Columbians services every day. They protect us from the heat, clean our air and water, pollinate our food, provide textiles and building material, and more. Additionally, by restoring the native vegetation that existed in Columbia prior to European invasion, we will be conserving Missouri’s natural heritage. 

Carbon Sequestration

Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide to reduce global climate change (USGS). On June 17, 2019, the City Council adopted Columbia’s first Climate Action and Adaptation Plan (CAAP). This plan is a road map to guide the City to zero carbon emissions by 2060. The CAAP actions for preventing further greenhouse gas emissions include increasing our City’s renewable energy portfolio and reducing the number of trips people make in personal vehicles. In addition, the CAAP also includes actions that address the climate change impacts that Columbia is already experiencing, such as flooding, increased frequency of large storm events and prolonged dry periods. These actions build more resiliency into our infrastructure, ecosystems and community. One major goal of the CAAP is to sequester carbon. 

The native wildflower plantings along Columbia’s roadsides will sequester more carbon than the existing turfgrass. This is because native plants have extensive root systems that can reach to 15+ feet deep (Figure 3). As a plant grows, it pulls carbon dioxide from the atmosphere and turns it into biomass. Most of the biomass in a native wildflower planting exists in the soil (in their roots), therefore, the carbon that is broken down by the plant and used to create biomass is now locked into the soil. Carbon that is locked into the soil can not contribute to climate change. Not only will the roadside native plantings sequester carbon, but this conversion will also reduce our mowing needs, thus decreasing our municipal carbon emissions.

Stormwater Runoff Mitigation

In Missouri, we have very hard, compact clay soils that the roots of turfgrass hardly penetrate. For this reason, turfgrass does not help prevent erosion or promote stormwater infiltration, resulting in a loss of topsoil, sediment pollution in our local streams and localized flooding. Native wildflowers and grasses solve these stormwater issues by having extensive root systems that create channels for stormwater to follow deep into the soil. These deep roots also hold the soil in place, preventing the erosion of stream banks. The more stormwater that is soaked up by the soil, the less water there will be to inundate and pollute our creeks. 

Contact Public Information Specialist for Public Works John Ogan at John.Ogan@CoMo.gov.