Family Poaceae

Reed Canary Grass is a huge problem – especially in the wetland, but also in woods, along paths, and in our remnant and planted prairies.   It’s very aggressive, and grows in thick circles that other plants have a hard time penetrating – animals and people find them almost impossible to walk through.  The circles grow larger in diameter with time.    This is an example of a circle of thickly growing RCG.

 

One interesting recent discovery is that most of the RCG populations in Minnesota are actually native, not from Europe.  Right now there’s no way to tell which populations are native except by genetic testing.  And even the native ones are extremely invasive.

I’ve tried spraying, mowing, cutting and treating the stems but I can’t get rid of it.   Even places where I’ve cut and treated or sprayed for years, the plants are still there.  The only thing we’ve found that helps is to damage the RCG by mowing or spraying, and then plant or encourage the growth of aggressive natives in between and around it.

Some of the plants we’ve found that compete successfully with the RCG are: sedges, Big Toothed Sunflower, Common Milkweed, Water Hemlock, Joe Pye Weed, Sneezeweed and Swamp Betony.   When we find a thick circle of RCG we mow it a few times just as it’s beginning to flower, which sets it back. After a few weeks, once it starts greening up again, (and if the ground underneath is dry) I sometimes spray with a grass-only herbicide. I try to ensure there are aggressive natives that will grow into the RCG area – either by planting seeds, or by making sure there are some growing nearby. The RCG doesn’t disappear, but it mixes with natives and becomes much less dominant.

This shows a circle of RCG in one of our planted prairies.  The soil here is dry, so I’ve sprayed it several times.  This shows it after one of the mowings, prior to greening up and spraying, in 2021.

 

This is the way that circle looked the following summer – 2022.  The RCG came back, but not as strongly, and there was lots of Common Milkweed.  This was about the second time it had been sprayed.  (I didn’t keep very good track of how many times I sprayed it.)  I sprayed again later that summer, then Mike mowed again the following summer, and I overseeded the mowed/sprayed area with some aggressive prairie plants.  I’m hopeful that this area will improve.

 

This is a different, wetter area, a little distance away – after Mike had mowed the RCG in preparation for spraying – October 2015.  In the late summer the ground is dry, so I was able to spray.  Again – I didn’t keep very good track of how many times I sprayed, but I think I sprayed twice – once with glyphosate, and the other time may have been with grass-only herbicide.

 

This is from June 2021 – still some RCG, but more sedges and other plants coming in.

 

August 2025 – RCG is still there, but much less dominant, and there are plenty of other flowering forbs.