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Invasive Grasses: A Burning Issue

A week or so ago, we all watched in horror as wildfires consumed the area around Lahaina on the island of Maui in Hawaii. What is often thought of as lush and tropical went up in flames in a matter of minutes and turned into a blazing inferno.

How could this have happened? Sadly, it was a combination of a downed power line and invasive, highly flammable grasses. Also, the lack of native vegetation allowed these invasive grasses to spread.

This is one of the reasons that we cannot stress enough that invasive plants are to be avoided and gardeners and landscapers should look to plant native species. Ignoring this principle is inviting disaster–one that could easily happen here, especially if native flora becomes overtaken by non-native grasses that are highly flammable.

The problem in Maui was also exacerbated by the fact that non-native animals – in this case goats – had eaten down quite a bit of the native vegetation allowing the invasive grass species to take over more easily. It’s always risky when something foreign is introduced into an ecosystem – flora or fauna.

Aside from being highly flammable, some of these grasses not only burn quickly, they grow back even stronger and spread even further after the fire.

Cogongrass (Imperata cylindrica)

One of the invasive grasses you will find here in the Southeast United States is cogongrass (Imperata cylindrica), also known as Japanese blood grass, or Red Baron grass.  This grass, which is native to Asia, Micronesia, Melanesia, Australia, Africa and Southern Europe is not native to the Southeastern United States and most likely arrived here accidentally in 1912 when it was used as packing material for imported goods.  According to the U.S. Department of Agriculture, it was intentionally introduced in Florida in the 1930s as possible fodder for livestock.

With the uncertainty of changes in the average conditions, such as temperature and rainfall, ecosystems aren’t always stable, and some areas are becoming more drought prone (like Maui). These flammable grasses are just tinder on the ground, waiting for a spark.

Cogongrass can grow to a graceful 2 – 6 feet tall and has a lovely silky tassel-like top, but do not let its beauty fool you. It not only edges out pasture grass and ruins golf course greens, it is a pyrophyte which means it is well known for its flammability.

Getting rid of cogongrass requires an integrated approach that destroys the rhizomes beneath the soil. After eliminating the cogongrass, it is important to introduce native plants as soon as possible to prevent a reinfestation. Pick a native species that can colonize quickly and is tolerant of the residual herbicide that was used in eliminating the cogongrass.

Imperata cylindrica red baron

This is a picture of a variety of Cogongrass ‘Red Baron’. It is still for sale in nurseries because it is considered ‘sterile’. Some states (Alabama right now) ban all sales of this grass because it can revert to the invasive green type. In my opinion, there are plenty of other grasses that can be used without introducing something that could cause us problems here in North Georgia in the future. https://www.missouribotanicalgarden.org/plantfinder/plantfindersearch.aspx

AB-Invasive-Chinese-Silver-Grass-Miscanthus-sinensis

This is another grass that I have seen escaping homeowners’ landscapes. It is also very flammable. Please do not plant this! It is still on sale at nurseries but is invasive and should not be planted. At one of my accounts, I planted it about 8 years ago, without knowing about its invasive status. Once I found out, I ripped it all out and replaced it with something else.

This is a good link about Chinese Silver grass: https://www.se-eppc.org/manual/MISI.html

Identifying invasive grasses and working to eliminate them now can prevent a horrifying disaster in the future.

The Georgia Land Conservation Assistance Network has a good section on invasive species divided into four categories based on how likely they are to cause environmental harm. You can find out more on their website at https://www.georgialandcan.org/.

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