Description
African Feather Grass (Pennisetum macrourum) is an erect perennial grass, sometimes growing to over 2 m high. The stems are upright, cylindrical and hairless, and emerge from a crown at ground level. The light green leaves grow to 1.2 m long and 1.2 cm wide, and are ribbed on the upper surface. They are a darker green on the lower surface and sometimes purplish along the edges and tips. The leaves are slightly curled and sometimes drooping. They emerge rolled inwards, later becoming flattened with the tips remaining rolled. The ligule (the structure where the leaf sheath and blade meet) is a fringe of hairs 0.5-1.5 mm long (Parsons & Cuthbertson 2001).
The flower head is pale brown to straw coloured, often with a purplish tinge. It is feathery, upright or drooping and long, thin, and spike-like, like a narrow foxtail. It is 10 to 30 cm long and 1 to 2 cm in diameter. The seed head is made up of numerous spikelets that are 5 to 7 mm long and surrounded by feather-like serrated bristles 10-15 mm long with one bristle longer and thicker than the rest (Thorp & Wilson 1998- ). The seeds are yellow to brown in colour and 5 to 7 mm long (Parsons & Cuthbertson 2001).
African Feather Grass has a network of fibrous roots which grow to a depth of 1 m. It also has sturdy rhizomes (underground stems) about 7 mm in diameter and up to 2 m in length. The rhizomes are partly enclosed in a sheath and occur from just below the soil surface to a depth of 30 cm (Parsons & Cuthbertson 2001).
For further information and assistance with identification of African Feather Grass contact the herbarium in your state or territory.
Distribution:
African Feather Grass occurs in discrete areas of Australia. In New South Wales it occurs in the Sydney metropolitan area and in small patches near Bega. In Victoria it occurs in the far south-west around Casterton, at Coalville, near Moe in Gippsland and scattered plants have been on roadsides near Geelong. In South Australia, it is found in moist areas in the Adelaide Hills and near Penola in the south-east. There are several small patches near Perth and it occurs in the Australian Capital Territory. In Tasmania it has occurred in the Huon and Derwent Valley (Parsons & Cuthbertson 2001; Navie 2004); each known infestation in Tasmania has been successfully treated and eradicated, however plants occasionally appear in other areas (Tasmania Department of Primary Industries and Water 2002).
Habit:
Grass
Key points:
- African Feather Grass (Pennisetum macrourum) is an erect perennial grass, sometimes growing to over 2 m high.
- It is a weed of roadsides, river banks, pasture and waste areas.
- African Feather Grass occurs in all states and territories except Queensland and the Northern Territory.
- It reproduces and spreads mostly by rhizomes.
- Dense infestations of African Feather Grass present a significant fire hazard, reduce biodiversity and block waterways.
- It can be controlled using a combination of cultivation, pasture improvement and herbicides.
How it spreads:
Infestations of African Feather Grass in Australia are mostly spread by rhizomes, with only minor spread by seed. Rhizomes may grow up to 1.0 m from the parent plant, and give rise to many small plants along its length. Rate of spread is somewhat dependant upon soil types, with greatest spread in lighter, sandy soils, and slower spread in heavy clay soils. Any activity that leads to disturbance of soil around African Feather Grass may allow small sections of rhizome to be picked up and moved around, for example, in soil and mud attached to machinery and implements. Strict hygiene practices such as thorough cleaning of equipment that comes into contact with the plant or soil should be followed whenever any work is carried out in the vicinity of African Feather Grass plants (Tasmania Department of Primary Industries and Water 2002). African Feather Grass produces large quantities of seed, although seed production varies from year to year. The seed is easily transported by animals due to the barbed bristles on the seed husk. It can also be moved on the wind for short distances, or carried along on water, such as periodic flooding of roadside channels (Tasmania Department of Primary Industries and Water 2002). Some spread can be attributed to human interest in the plant for dried flower arrangements and for ornamental purposes in landscaping (Parsons & Cuthbertson 2001). The seeds exhibit a high level of viability, however, they appear to remain viable in soil for only a few years. Seedling establishment levels are quite low, possibly due to the seed’s requirement for a fine soil cover and adequate moisture for successful germination (Tasmania Department of Primary Industries and Water 2002).
Where it grows:
African Feather Grass prefers subtropical to warm-temperate climates and grows on open, well drained soils (Johnson 2005). It grows in lowland grassland and grassy woodland, along the banks of rivers and creeks, in seasonal freshwater wetlands, roadsides, pasture, and low-lying areas subject to flooding, spreading to drier surrounding areas and waste areas where adequate moisture is available (Blood 2001). It is often found on sandy soils (Thorp & Wilson 1998 - ) and tolerates drought, wind, salt and grazing (Blood 2001). It requires full sun, with dense infestation only rarely occurring within shaded bushland environments (Tasmania Department of Primary Industries and Water 2002).
Flower colour:
Yellow, Purple
Impacts:
African Feather Grass has proved a useful plant for soil stabilisation, particularly around road verges (Tasmania Department of Primary Industries and Water 2002). However, dense infestations presents a significant fire hazard, reduces biodiversity by excluding native flora and blocks waterways and access to them (Johnson 2005). Large infestations are an ideal haven for rabbits and feral cats (Tasmania Department of Primary Industries and Water 2002).
The leaves are quite tough and coarse and are low in nutritional content. They are rarely grazed by stock, even in times of low available feed (Tasmania Department of Primary Industries and Water 2002).
Origin:
African Feather Grass is a native of South Africa (Parsons & Cuthbertson 2001).
History:
Introduction of African Feather Grass to Australia is believed to be as a result of contamination of hay brought back with horses after the Boer War. It was first recorded near Casterton in the Western District of Victoria in 1904 (Parsons & Cuthbertson 2001).
In New Zealand, African Feather Grass was apparently introduced as a soil binder at about the end of the 19th century and was later promoted as an ornamental plant because of its attractive long, feathery flower heads (Parsons & Cuthbertson 2001).
