This is a good year for sensitive briar (Mimosa quadrivalvus) in the Platte River Prairies. Sensitive briar is a spiny perennial legume that sprawls across the ground in dry prairies and has leaves that fold up when touched or blown about by the wind. It’s an odd plant, and one that is hard to miss when it’s blooming because each plant has numerous pink flower balls scattered across an area about the size of a large bathtub.
Sensitive briar is named for the sensitivity of its leaves to touch, but it must also be sensitive to moisture conditions or something else. As I was preparing to write this, I scanned through my field notes because I remembered sensitive briar being extra abundant a few years ago as well. I was right; I’d noted an extraordinary number of plants back in 2011. In fact, I wrote a blog post about it! I don’t have any better explanation this year than I did back in 2011 for why this perennial plant seems to ebb and flow so much in abundance.
Maybe the ebb and flow is mainly about flowering, and many of our sensitive briar plants just don’t bloom every year. The only thing giving me pause is an experience we once had with a large plot of sensitive briar plants in our seed production garden. One year, we thought all the plants had died because they didn’t even come out of the ground that spring. We wondered if they’d been accidentally sprayed or something the previous year. Fortunately, we didn’t till the plot up and start over because the next year it was filled with mature sensitive briar plants again! It’s not that I’m looking for more data collection projects to work on, but it would sure be interesting to mark some plants in our prairies and track them over 10 years or so to see what’s going on…
Just one more fun prairie mystery to solve!