Cogon grass (Imperata cylindrica): spread and control

Updated on 22 September 2026Published on 18 December 2020

Native and invasive range of Imperata cylindrica

While colonization among people is often subject to debate, regarding plants it can sometimes be dramatic. When Imperata cylindrica spreads outside of its native range, it turns invasive and disturbs entire ecosystems.

Check whether you should refrain from planting it in your area.

Imperata cylindrica at a glance: where it belongs and where it does not
Native to	SouthEast Asia
Invasive in	Rest of Asia, Oceania, Africa, America (North, Central and South), Europe

Where does cogon “Bloodgrass” come from?

Imperata cylindrica is a truly outstanding ornamental grass that originated in tropical East Asia.

Several cultivars exist which aren’t very invasive, such as the ‘Red Baron’ bloodgrass. However, such cultivars are never perfectly stable. Sometimes they revert to the original, aggressive form. When this happens, it becomes difficult to control cogon grass’s spread.

Today, a vast number of states and countries around the world include this type of grass on their “Top invasives” lists.

Map of the world where Imperata cylindrica is native or invasive

Native range – Thailand, Philippines, Japan, portions of East China. Some strands are native to East Africa, as well.

Invasive range – A great many countries officially list “bloodgrass” as an invasive plant:

Southern and Eastern Europe – Albania, Armenia, Croatia, Cyprus, France, Greece, Portugal, Slovenia
Asia – Afghanistan, Azerbaijan, Bhutan, Cambodia, Sri Lanka, Turkey, Turkmenistan, Russian Federation, Kyrgyzstan, Uzbekistan, Laos, Myanmar, Nepal, India, Pakistan
Africa – Algeria, Benin, Burkina Faso, Burundi, Seychelles, Senegal, Sierra Leone, South Africa, Swaziland, , Cameroon, Congo (both), Ivory Coast, Egypt, Ethiopia, Togo, Tunisia, Malawi, Mayotte, Mauritius, Morocco, Mozambique, Namibia, Nigeria, Kenya, Rwanda, Mali, Lebanon, Lesotho, Liberia, Libya, Uganda, Zambia, Zimbabwe, Gabon, Gambia, Ghana, Guinea
Middle East – Syrian Arab Republic, Saudi Arabia, Oman, Yemen, Israel, Iran, Islamic Republic Of, Iraq, Jordan, Armenia, Georgia
North America – United States
South America – Argentina, Bolivia, Chile, Colombia, Uruguay, Peru, Venezuela
Oceania – Australia, American Samoa, Tanzania, Solomon Islands, Christmas Island, Tonga, Micronesia, Philippines, Samoa, Malaysia, New Caledonia, New Zealand, Indonesia, Palau, Fiji, Northern Mariana Islands, Vanuatu, Guam

Even in countries where it’s native, governments sometimes declare it a pest or a noxious weed.

Map of native range of Imperata cylindrica

Map of the world with imperata cylindrica native areas in green, around the Philippines and in Asia — Its native range runs from Southeast Asia to East Africa

Reporting Cogon bloodgrass in the United States

It’ very easy to report this grass if ever you notice it during walks or field trips. For the USA, simply head over to the EDDMapS website, create a login, and report the grass. Thanks to people like you who do it, they can create the map below, accurate down to county level. It helps local environment agencies set their priorities straight.

If you’re down under, click here to report Imperata cylindrica in Australia.

Before reporting a suspected cogongrass (Imperata cylindrica) infestation, check the tell-tale signs: an off-centre whitish midrib on each blade, finely serrated leaf edges, and a silky white cylindrical flower plume.
Broken rhizomes travel on boots, tyres and mower decks, so brush off your footwear and equipment before leaving a suspected infestation.

Regulations regarding Imperata cylindrica

In the United States, several states have legislated against sale, growing, and transporting cogongrass. Usually this pertains to the live forms (rhizomes and seeds).

The map below shows which states have taken legal action to contain the I. cylindrica cogon grass:

In the United States cogongrass is listed as a federal noxious weed, so importing it or moving it across state lines requires a USDA APHIS permit.

Learn more about invasive bloodgrass

Planting imperata cylindrica in pots — A pot keeps the running root system contained

Interestingly, almost all invasive cogon grass in the United States can be traced back to a meager 4 individual plants! A genetic analysis revealed that the genetic diversity was minimal. Four patches of grass now endanger the entire environment of the American South-East!

Accordingly, the first were a few rootlets that fell out of an orange crate delivered from abroad to Alabama. Then, since the plant seemed to be a promising grower, it was introduced with the idea of providing fodder for cattle. By the time they realized cows hated eating the razor-sharp blades, it was too late. Controlling invasives back then didn’t have the importance it has now.

Controlling cogongrass

Very difficult, due to the extensive root system.

Burning won’t eliminate the plant. Usually, it even triggers blooming!
Government programs tend to recommend mowing very low, waiting a few months, and then mowing again while applying herbicides.

Ways of dealing with cogon grass, and what each one actually achieves

Cogon grass is hard to beat because of its root system, and not every method works. Here is what the article says about each approach.

Ways of dealing with cogon grass, and what each one actually achieves
Approach	How it works	Result
Burning	Fire removes the top growth only	Does not kill the plant and often triggers blooming
Mowing then herbicide	Mow very low, wait a few months, mow again while treating	The approach government programs recommend
Growing in pots	The container confines the rhizomes	The plant can still be grown without spreading
Choosing a tamer cultivar	Selected forms are far less aggressive	Safer, but they can revert to the wild type

Whatever the method, the extensive root system is what makes control so difficult.

Smart tip about cogon grass

A brilliant way to still grow these plants is to plant them in pots. That way, they won’t spread through their root system. Normally, varieties like the Imperata cylindrica ‘Red Baron’ don’t go to seed easily. They aren’t as dangerous as the original cogongrass lineages.

Frequently Asked Questions

Is it legal to plant Imperata cylindrica?

It depends entirely on where you garden. In the United States, several states have passed laws against selling, growing and transporting cogongrass, usually targeting the live forms such as rhizomes and seeds. Even in parts of its native range, governments sometimes classify it as a pest or noxious weed, so check your local rules before planting.

Can I grow blood grass in my garden without it spreading?

Growing it in a pot is the sensible answer, because the container stops the root system from running. Named forms such as ‘Red Baron’ also rarely set seed, which makes them far less risky than the original cogongrass lineages. Bear in mind, though, that such cultivars are never perfectly stable and can revert to the aggressive wild form.

How do you get rid of cogon grass?

Control is very difficult because of the extensive root system. Burning is not the answer: it fails to eliminate the plant and usually triggers blooming instead. Government programs tend to advise mowing very low, waiting a few months, then mowing again while applying herbicides.

How did cogon grass reach the United States?

The first plants were a few rootlets that fell out of an orange crate shipped from abroad to Alabama. As the grass seemed a promising grower, it was then introduced deliberately as cattle fodder, but cows refused the razor-sharp blades and by then it was too late. Genetic analysis shows almost all invasive cogon grass in the country traces back to just four individual plants.

Sources (maps and research)GSID, as of early winter 18^th, 2020
EDDMapS
Institute for Plant Genomics and Biotechnology, Department of Horticultural Sciences, Texas A&M University

Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Just grass, but so invasive! by Rob Bakker under Public Domain
Great way to control it by Daryl Mitchell under © CC BY-SA 2.0
World Map base by Smurfy under © CC BY-SA 3.0

Written by Gaspard Lorthiois | Loves helping out, especially when it comes to growing things. Worked in herbal medicine, runs a farm, and dabbles in tech. Master's degree and engineer.

La page de Gaspard Lorthiois