Blady Grass

Imperata cylindrica (L.) Raeusch. var. major (Nees) C.E.Hubb

Synonyms - Lagurus cylindrica, Imperata arundinacea

Family: - Poaceae


Imperata commemorates Ferrante Imperato a Neapolitan botanist

Cylindrica refers to the cylindrical seed head.

Other Names


Cogongrass (USA)



A tall, rhizomatous, spreading or tufted, perennial grass with silky white seed heads. The leaves are erect, about 2 cm wide and have a white, off-centre mid vein. Ornamental varieties may have red leaves.




First leaves:


Blade - Usually green but ornamental varieties may be red. White, off-centre mid vein.
Ligule - membranous, 0.5-1 mm long, flat topped. Tufts of hairs.
Auricles -
Sheath - Edges often hairy. Older ones often split into fibres.

Blade - Narrow especially at the base where it looks like a petiole, 150-1500 mm long by 4-20 mm wide, flat or in rolled, strongly keeled. Stiff, prominent midrib. Tip pointed, Edges parallel and rough and often with hairs. Hairy near the mouth.


Low lying and spreading to somewhat erect up to 800 mm tall, rarely bent at the nodes. Tufts of hairs on nodes. From underground rhizomes.

Flower stem -

Flower head:

Silky white, fluffy, erect, slender and cylindrical spike like raceme, 70-600 mm long . Appears speckled at flowering due to purple anthers. Spikelets fall when ripe leaving an almost bare stem. Branch axis not jointed.


Spikelets - 3 or in pairs, all alike, 3-6 mm long, on unequal stalks, 1 or rarely 2 flowered, covered in fine white silky hairs attached to the base or the back of the glumes.
Florets - bisexual.
Glumes - About equal length, membranous, 3-9 nerved, membranous, hairless on the back
Palea - hyaline, nerveless, flat topped and torn near the tip, smaller than lemma.
Lemma - 2, shorter than the glumes. First is hyaline, sterile or male, nerveless or 1 nerved. Second is hyaline, bisexual, oblong, ovate and nerveless.
Stamens -
Anthers - Purple




Underground rhizomes covered in membranous scales.

Key Characters:

Inflorescence not enclosed in leaf sheath.

Panicle spike like, cylindrical, soft and silky with numerous fine white hairs obscuring the spikelets, bristles not present.

Spikelets falling entire, dorsally compressed, awnless, commonly paired, pedicellate, not sunk in notches in the rachis.

1 bisexual floret per spikelet.

Glumes villous, not awned, stiffer than membranous lemmas, as long as or longer than the lemmas

2 Lemmas, not awned.

Purple anthers often conspicuous among the hairs.

Adapted from John Black and Nancy Burbidge.


Life cycle:

Perennial. Forms dense or loose clumps.



By seed and rhizome.

Flowering times:

January to May in SA.

Seed Biology and Germination:

Vegetative Propagules:


At least 5 varieties. Variety major is the most common.

Population Dynamics and Dispersal:

Spreads by seed and underground stems. Increases as grazing intensity increases.

Origin and History:

Temperate to tropical Asia.

Introduced for forage, a soil stabiliser and as an ornamental.



Widely distributed around the world.




Temperate, tropical and subtropical


Tends to grow on poor low fertility soils.

Plant Associations:



Grazed when young unpalatable when older.


Used for thatching.

Soil stabiliser.


One of the "Worlds Worst Weeds". It is a weed of 35 crops in 70 countries.

Weed of roadsides, mine sites, Pine plantations, desert dunes, wetlands, Rotation crops, perennial crops, savannahs and forests.

Environmental weed of the USA.

Poor habitat for wildlife.

Highly flammable.

Weed of fire and shifting cultivation in developing countries.

The red ornamental cultivars eg "Red Barron" do not appear to be as invasive as the green varieties but they have cold tolerance. Planting is discouraged to reduce the risk of crossing with native varieties which may introduce cold tolerance into the weedy varieties.


Not recorded as toxic.




Noxious weed of the USA.

Management and Control:

Don't burn because this usually leads to greater infestations.

Establish more desirable perennial grasses, then mow or graze.

Fertilise the area and correct nutritional deficiencies.

Disc cultivation usually provides reasonable control.

Grazing tends to lead to increased infestations


Eradication strategies:

Mow, graze, disc cultivate then treat regrowth with 1 litre of glyphosate per 100 litres of water or imazapyr. Fertilise to encourage other species.

In areas that can't be cultivated, burn in spring/summer and apply glyphosate in autumn.

In gardens dig it up and remove all underground stem fragments and burn them.

Herbicide resistance:

Biological Control:

Related plants:

No other weedy species in this genus in Australia.

Plants of similar appearance:


Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P48. Photo.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P 2245. Diagrams.

Bodkin, F. (1986). Encyclopaedia Botanica. (Angus and Robertson, Australia).

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P70. Diagram.

Ciba Geigy (1980) Grass Weeds 1. CIBA GEIGY Ltd, Basle, Switzerland. P63. Diagrams.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney).

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Cowley, K. and Hohnen, P. (1997). CSIRO handbook of Australian Weeds. (CSIRO, Melbourne). #530.1.

Paterson, J.G. (1977). Grasses in South Western Australia. (Western Australian Department of Agriculture Bulletin 4007). P58. Diagrams.

Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne).


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