Prairie Restoration, Part 1: Preparing the Site

Ever since we were awarded the US Fish and Wildlife Service grant this summer, we’ve been busy preparing the sites at Charles Ilsley Park and Draper Twin Lake Park for prairie restoration! It is very important to prepare our restoration sites properly before planting. Otherwise our prairie plants won’t establish very well and we will probably have big problems with weeds. So how do we prepare for planting a prairie?

  • Step 1: Figure out what is already growing. Are the plants mostly native or non-native? Are there lots of trees or shrubs, or only herbaceous (non-woody) vegetation? Do we have many invasive plants (glossy buckthorn, autumn olive, multiflora rose, swallow-wort, etc.)? A quick search in the old field at Draper Twin Lake Park found 45 plant species, 20 non-native and 25 native (click here to see the list). Only a few of the the native species I found are considered “conservative” species – species that tend to grow in high quality native plant communities. Based on these observations, the existing plant community doesn’t appear to be of high quality.
The current plant community in the old field at Draper Twin Lake Park consists mostly of non-native species and "weedy" native species.
The current plant community in the old field at Draper Twin Lake Park consists mostly of non-native species and “weedy” native species.
  • Step 2: Make an action plan based on the observations. After we initially look at the site, it was very tempting to just jump out there and start working. However, we took a little more time to develop our observations into an action plan. We also noticed that box elder (Acer negundo), autumn olive (Elaeagnus umbellata), and black locust (Robinia pseudoacacia) were establishing thick stands. Some of the black locust had grown nearly 20 feet tall in the four years since the field was plowed! These needed to be removed before we could even think about planting. Based on our quick botanical survey, we knew that we didn’t have a high quality plant community in the field. Therefore, the best route – the option that will ensure the highest establishment of native prairie species and fewest problems with weeds – was to remove all of the existing vegetation and start over from bare soil. We won’t till the soil, though, as that will expose more weed seeds that have built up in the soil seed bank.
    Black locust at Draper Twin Lake Park.
    Black locust at Draper Twin Lake Park. These trees are not native to Michigan. They sprout readily from stumps and roots, and can be very difficult to control. We think that these grew so quickly because they sprouted from the roots of trees along the edge of the field.

    Box elders at Draper Twin Lake Park
    Box elders at Draper Twin Lake Park. Although a native tree species, box elders are found in many different habitats and often establish quickly on bare soil.
  • Step 3: Remove the trees and shrubs. Based on our observations of the current plant community at Draper Twin Lake Park, we feel confident that we can improve the plant community and wildlife habitat by replanting after removing as much of existing vegetation as possible. For all of the large trees and shrubs in the field, we used brushcutters and a chainsaw to chop them off at ground level. We then daubed the stumps with herbicide to prevent re-sprouting.
Searching for cut stumps to daub with herbicide.
Searching for cut stumps to daub with herbicide.
We stacked the cut brush in piles.
We stacked brush into piles.
  • Step 4: Mow the field. After removing the woody plants, we mowed the field at Draper Twin Lake Park to remove any smaller shrubs and to prepare the field for herbicide application.
Mowing the field at Draper.
Mowing the field at Draper Twin Lake Park.
  • Step 5: Herbicide Application. To give the native seeds the best chance to succeed, we treat the field with herbicide to kill existing vegetation. If we find any special native plants we avoid that area or cover individual plants. Most of the areas we treat have very few native plants remaining.

And that is our site preparation process. Site preparation will change depending on what is already growing  at the site, what your restoration goals are, and what resources you have available. In every case, taking the extra time to learn about the site, develop an action plan, and thoroughly prepare the site will save you time and money in the long run. We’ll keep you updated as we continue this process!

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About Ben VanderWeide

I am the Natural Areas Stewardship Manager for Oakland Township Parks and Recreation in southeast Michigan. I have a doctorate in biology (focused on plant ecology) and I am passionate about protecting and managing natural areas.

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