Project Types

Turf Grass

Besides native landscaping, you might also consider low-input turf grass, which provides property owners with benefits including reduced water use, fertilizer, and maintenance expenses. The environmental benefits include more opportunities to reduce run-off. While this is not as robust as conserving or restoring natural habitat, it can be an impactful incremental improvement where habitat restoration is not possible or practical. The University of Minnesota, Turfgrass Science provides resources and assistance to those interested in looking at low-input turf options. For more information, watch this informative video of Sam Bauer sharing information on the low-input turf laboratory on the University of Minnesota campus. Explore turf options with your landscaper and/or facilities management team.

Expectations and Implementations

General Mills

General Mills facilities manager relayed his expectation for prairie—especially as they are working to implement more beyond their current eight acres:

• In one year, if the prairie had been planted in spring with no irrigation, you would be lucky to see six inches of growth, and you will see hardly any flowers
• In two years, the prairie will likely be fairly dull looking and be particularly “weedy” looking to people who do not know what to expect, especially if using flower mixes. Plant growth is likely to be waist high to over six feet tall, depending on the seed mix.
• Maintenance in the first two years is usually fairly easy as General Mills’ prairie vendor comes in to mow it and take down the weeds.
• In the third year and thereafter, spot spraying will take place to try to get rid of different unwanted plants and invasive species.
• Water to help with any trees that are incorporated into the prairie—and to help with maintaining any existing sub-surface sprinkler systems.

To help prevent the spread and takeover by thistle, prairie along pond edges and in parking lots are burned every year, while wood edges and larger prairie sections are burned about every three years. Some flower species, such as Black-Eyed Susan, will germinate in the fall but only 1/8th will survive into the spring. Being careful with seed mixes is important to keep the prairie looking fuller and having decent mixes of flowers throughout the summer. Pay attention to some of the other nearby land uses; turf does better with salt and sand on it than prairie does. General Mills tries to keep prairie eight feet back from sidewalks and parking lot snow drifts, especially if the area does not drain well or if it is flat.

Cost Considerations

Converting from a turf grass lawn to a natural, native landscape does cost more in the first year of implementation, compared to the existing cost to upkeep a turf lawn. However, with five acres or more converted, payback often occurs in as little as two years. With lower maintenance and watering needs, it pays back fairly quickly. Once established, the maintenance costs of natural and prairie plantings can be as low as 1/10th of the cost of maintaining a lawn. Native landscaping with stormwater retention practices like rain gardens, bio-retention areas, and swales can provide more significant monetary benefits such as the reduction or eliminate stormwater fees charged to businesses by municipalities. According to Richard Murphy, Murphy Warehouse is one of the largest businesses “in the city of Minneapolis not to pay a stormwater fee, which would run over $73,000,” due to his stormwater and prairie plantings.

General Mills

While General Mills has not done a full account of the cost differences between turf and prairie, they have not seen much of a difference in cost. The cost is not that different because they only apply 0.9 pounds of fertilizer per acre to their turf in the fall—which is far lower than most turf acres. The turf is mowed more often but is better able to survive salt conditions over winter, so there is not as much maintenance to repair turf in the spring compared to prairie.

The Metropolitan Council

The Metropolitan Council has found installation of prairies and other native landscapes provide cost savings compared to the typical maintenance of turf landscaping. The Empire Wastewater Treatment Plant infiltration basins are two acres of native vegetation, which were constructed to treat stormwater as part of a wastewater treatment plant expansion. The basins were originally seeded with Minnesota native prairie plants. The Empire Wastewater Treatment Plant wetland is a 50-acre wet meadow wetland that was formerly a wet cornfield. In this project, the Metropolitan Council re-sculpted the site, seeded, and sponsored volunteer planting of shrubs through the nonprofit Friends of the Mississippi River. The estimated, typical cost of mowed turf per acre is approximately $600 to $1,000 per acre per year. These graphs show the cost breakdown for the projects between site preparation, maintenance, seeding, supplemental seeding, and burns. While site preparation and initial maintenance costs are high, costs are usually far under that of typical turf maintenance within a few years.

Expectations and Implementation

General Mills

General Mills has 9,000 square feet of green roofs in Minnesota. Each of the roofs is different and requires its own set of maintenance strategies. One, with shrubs and 20 inches of good soil, has not been watered since 1992. Two new ones implemented in 2011, have soil ranging in depth from 4 inches along the edges to 14 inches in the middle. For these roofs, if it has not rained for a week or so, they are watered.

More information coming soon

• What might the project area require each year?
• What it will look like in year 1 vs. year 3?
• What to anticipate with different kinds of fauna?
• What are things you should be thinking about to make sure this project is successfully implemented?

Cost Considerations

General Mills

For General Mills, the general maintenance cost of 9,000 square feet of green roofs is about $5,000 a year, with the additional cost of fertilizer every other year.

More information coming soon

• What is the general expected ROI from this type of a project?
• What are some of the costs you can expect?