Is this plant invasive?

The wild species is extremely invasive. The Red Baron cultivar spreads less aggressively, but it is not fully sterile, can revert to the invasive green form and is restricted in some regions, so check local rules and remove any green shoots promptly.

Use physical barriers to contain rhizomes or choose sterile cultivars to prevent unwanted spread.

Plant guide

Cogon grass.

Imperata cylindrica

Pronounced im-per-AH-tuh si-LIN-dri-kuh

Also known as Alang-alang, Blady grass, Cogon grass, Japgrass, Satintail, Speargrass, American Grass, Beady Grass, Bedding Grass, Bladey Grass, Blady grass, Cogongrass, Cotton Wool Grass

Cogon grass is a highly aggressive perennial grass known for its striking, sharp, and upright blades. It spreads rapidly through an extensive underground root system, making it quite difficult to manage in garden settings. Please be aware that this plant is considered a serious invasive species in many parts of the world.

At a glance

Care level: Easy
Plant type: Perennial grass
Light: Full sun
Indoor light: Direct sun
Water: Every 7 to 14 days
Mature size: 4 feet
Growth rate: Fast
Hardiness: USDA 6 to 10
Bloom time: Late spring to early summer

Care

This grass thrives in full sun and tolerates a wide range of soil conditions. Watch for rapid spread into unwanted areas, as its rhizomes can easily choke out other plants. It is best to avoid planting this species due to its invasive nature.

Watering: It is quite drought tolerant once established.
Feeding: It rarely needs extra food as it is very vigorous.
Pruning: Cut back dead foliage in late winter to encourage fresh growth.
Repotting: It grows very quickly and will need a larger container often.
Soil: Well draining sandy or clay soil
Soil pH: 4.5 to 7.5
Temperature: -20 to 35°C
Humidity: 40 to 80%
Drought tolerance: Moderate
Lifespan: Perennial, typically 5 to 10 years.
Deer and rabbits: High

Signs it needs repotting

Roots growing out of the drainage holes.
Water sitting on the surface of the soil.
The plant stops producing new red shoots.

Safety

People: The foliage can have sharp, serrated edges that cause skin cuts and irritation.
Pets: This plant is generally considered non toxic to cats and dogs.
Children: The sharp leaf edges pose a risk of paper cut style injuries to children handling the plant.
Contact allergens: The leaves have fine, sharp serrations that may cause mechanical skin irritation.
Airborne allergens: The windborne seeds or pollen can trigger allergic reactions in sensitive individuals.
Edibility: The plant is not considered edible and contains chemical compounds that can be irritating if ingested.

How to identify it

Sharp, serrated leaf edges
Bright green, pointed blades
Dense, fluffy white flower plumes
Extensive underground rhizome network
Off center leaf midrib

Height: 0.3 to 1.2m
Spread: 0.3 to 0.9m
Leaves: green, red, deciduous
Flowers: silver, white, 5 to 20cm

Problems to watch for

Root SuckeringCommon
RustUncommon
SmutUncommon
Stem BorersRare

Invasive spread · The species spreads rapidly via underground rhizomes and is difficult to eradicate once established.

By symptom

Plant problems by symptom

Check your cogon grass from a photo

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Growing it

Propagation: division, rhizome cuttings
When to plant: spring, autumn
Overwintering: Cut back the dead foliage in late winter before new growth appears. Mulch around the base if you live in a region with very harsh, freezing winters.
In containers: It grows well in containers, which is an excellent way to keep the invasive rhizomes under control.

Division

Dig up the clump in early spring.
Use a sharp spade to divide the root mass into smaller sections.
Ensure each section has healthy rhizomes and foliage.
Replant immediately in well draining soil.

Plant in a contained area or use a root barrier to prevent the rhizomes from invading the space of neighboring plants.

Grows well with

Black Eyed Susan · The bright yellow flowers provide a nice color contrast to the red foliage.
Stonecrop · These succulents thrive in similar sunny conditions and offer a different texture.

Similar species

Japanese Blood Grass · This is the most common ornamental version of the species.

Science

Family: Poaceae
Genus: Imperata
Order: Poales
Class: Liliopsida
Native range: Tropical, subtropical and warm temperate regions of Asia, Africa, southern Europe and Australia.
Conservation: The wild species is considered a highly invasive weed in many parts of the world and is banned in several regions.

It is a pioneer species that quickly colonizes disturbed soil and outcompetes native vegetation through dense rhizome networks.

Value to wildlife: provides dense cover for small insects
Pollinators: bees, butterflies
Uses: ornamental grass, erosion control, garden accent

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 3/9
Soil reaction: 5/9
Light: 7/9
Temperature: 7/9
Moisture: 5/9
Nutrients: 4/9

Taxonomy resolved against GBIF.

Questions people ask

Is this plant invasive?: The wild species is extremely invasive. The Red Baron cultivar spreads less aggressively, but it is not fully sterile, can revert to the invasive green form and is restricted in some regions, so check local rules and remove any green shoots promptly.
How do I control it?: Use physical barriers to contain rhizomes or choose sterile cultivars to prevent unwanted spread.

Where the name comes from

Imperata honors the Italian botanist Ferrante Imperato, while cylindrica refers to the cylindrical shape of the flower spikes.

Good to know

It is known as Cogon grass in its native range.
The red tipped leaves of the Red Baron cultivar turn a deep burgundy in autumn.
It is one of the top ten worst weeds in the world according to some agricultural organizations.
The plant is highly fire adapted and often thrives after controlled burns.

Also in

Deer-resistant plants

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.