"Experimental wedge" - 4 year review

2011 marked the 4th growing season for what I call the "experimental wedge". This is a tiny little corner of Lily's Prairie where I experimented with planting prairie seeds in an unconventional way and didn't quite know how it would eventually work out. Looking back now though, it is very clear that this was not only my most successful method of prairie reconstruction, but also the quickest and most effective way of converting old cool-season hay fields into a diverse native tallgrass prairie. Picture below shows the area before restoration began.

Today the experimental wedge is dominated by two native warm-season grasses; indian grass and big bluestem grass. The old hay fields at the south end of Pinefield Farm, along White Lake Road, are classified as dry-mesic prairie for the most part (there are some areas where water stands for extended periods in the spring and therefore are classified as mesic and wet-mesic). These two native warm-season grasses would have been dominant in a dry-mesic Michigan prairie, and so is considered a success from that standpoint. I also planted wild bergamot, stiff goldenrod and butterfly weed in this area to add a little extra diversity, but I'll admit, my first objective was to eliminate the cool-season grasses and get the warm-season grasses established before I really added forb's to the mix. Picture below to the right shows the planting during the burn before we seeded the area.

In the second and third growing seasons (2009 & 2010), wild bergamot and stiff goldenrod really had a presence in this planting. Indian grass was the first to establish seed heads (a couple plants set seed the first year), but big bluestem is gaining momentum and the two are starting to balance out now. This year, wild bergamot had been reduced to about a quarter of its original presence, and stiff goldenrod is overabundant. Butterfly weed flowered during the third and fourth growing seasons, but the grasses are too thick now and it had trouble competing with their height for sunlight. I'm starting to think that this area would have almost been considered mesic, because even with the slope, the soil can hold significant amounts of moisture and is considered very fertile. Grasses would have outnumbered wildflowers in terms of quantity (not species) in a tallgrass prairie, so having the two grasses dominate seems appropriate. Picture below to the left shows the planting at the end of the second year.

The experimental wedge started in the spring of 2008 when I removed an old goat and chicken pen that I had assembled 10 years prior. After removing the fence, I wanted to redesign how the prairie transitioned into the yard area and so spent time designing and experimenting with different mowing patterns to create the edge of the tallgrass prairie. Once I was happy with the outline of the prairie, I decided to experiment with the corner closest to the barn and get some prairie plants growing so that I could further visualize future prairie reconstruction areas and start to understand the behavior and scale of the tallgrass prairie. I knew that the cool-season grasses would be aggressive and difficult to control against a warm-season dominated planting like a tallgrass prairie. Therefore, I experimented with a herbicide application that focused the most destruction to cool-season plants during a time of the growing season when they are most vulnerable. I sprayed the planting area of the experimental wedge with glyphosate, a non-specific herbicide, at the end of May, 2008. This is a time of year when conditions are warm during the day, cool at night and there is ample rainfall. Perfect for the growth of cool-season plants. After about two weeks, the plants in the wedge were all dead and brown, acting as a perfect fuel for a prescribed burn. This burn which took place in early June, removed all the dead thatch of the cool season grasses and prepared the soil for planting. By now, the nights were getting warm and the daytime temperatures were getting hot - perfect for the germination and establishment of warm-season prairie plants. Immediately following the burn, I planted a heavy amount of indian grass, big blue, wild bergamot, stiff goldenrod and butterfly weed. The wildflower seeds had been cold-moist stratified over the winter in my fridge, so they were ready to grow as soon as I planted them. Everything established quickly and has made for a very successful planting method. Picture below to the right shows planting toward the end of the third growing season when big bluestem has gone to seed, but before the indian grass has matured.

I truly attribute the success of this planting by the ruthless attack against the cool season plants early on, which reduced the competition for the prairie seedlings during their first couple of growing seasons. After they get established, they are able to hold their own and compete effectively against the non-native plants. The only reason why I didn't continue to use this method for the rest of Lily's Prairie was due to the heavy use of chemicals and the difficulty of burning a large area in the middle of the growing season when the weather is unpredictable. I opted for a more organic method of converting old hay fields into native grassland. More experiments will be required in the future to get good results without the use of poison chemicals. The only threat that I see now is the spread and growth of canada goldenrod (which is native, but was not planted) against the native grasses, so this will be interesting to watch over the next four years... Picture below to the left shows the big bluestem dominating in the fourth growing season!