Stiff tufted perennial grass 20-80 cm high with flat or in-rolled leaves and a taller, narrower, olive-green spike-like panicle
Flower stems are hairless
Ligule is a ring of short hairs up to 0.5 mm long
Leaf blades are in-rolled, 0.2 to 2 mm in diameter, or flat and up to 5 mm wide, 10-25 cm long, hairless on the upper surface but rough on the ribs and margins on the lower surface
Flower head is 9 to 22 cm long, 4-8 mm wide, more or less continuous but with some separate branches at the base. The branches have densely crowded spikelets
Spikelets are 2-3 mm long, black-green in colour, one-flowered, with the yellow-brown seed falling free of the glumes at maturity
Leaves and stem are very tough and difficult to break.
Biology
Origin
Originated in eastern Africa, from South Africa to Ethiopia
From there it has been spread into North and South America, southern Asia, Indonesia, Hawaii, the South Pacific islands, Australia and New Zealand
First record of its occurrence in New Zealand was earlier than 1840. It was introduced into Australia probably at about the same time and there it is known as Parramatta grass.
Life cycle
As a C4 species, Sporobolus africanus is most active in summer and is very drought-tolerant
Prolific seed producer and can shed as many as 3,600 seeds per square metre each year
Plants are perennial, surviving light frosts in winter and showing renewed growth in summer
In New Zealand pastures, most often seen on the dry, sunny faces of hill country
Benefits
There are few productive uses for this grass. It is of very low value as animal forage.
Impacts
Sometimes a problem in lawns where it is partially resistant to mowing
Can grow through and break up asphalt on the edges of roads
Impact on pasture
Very low value as animal forage and, in pastures, it can therefore replace more productive species
Highly resistant to treading and partially resistant to grazing.
Impact on livestock
No direct effects of this grass on livestock have been reported
Control
Physical control
Where infestations are relatively small, plants can be hand chipped, bagged and removed from pasture for burning or similar destruction
Topping of the grass will reduce its seed set.
Grazing management
The best way of preventing invasion of this species is by maintaining a good tight sward of locally appropriate forage grasses, using an appropriate fertiliser regime and good grazing management
Do not overgraze dry sunny hill slopes.
Chemical control
Glyphosate can give adequate control of this species. Glyphosate is non-selective and will also kill
other grasses and clovers but can be used in three ways:
1. Applied at a low rate (usually half label rate) and then allow the natural pasture grasses and legumes to regenerate
2. Applied at a full rate and reseed the pasture either by air or by hand for smaller infestation
3. Applied in concentrated form in a weed wiper when ratstail is flowering and stands out above other pasture species.
Champion P, James TK, Popay AI, Ford K, 2015. An Illustrated Guide to Common Grasses, Sedges and Rushes of New Zealand. New Zealand Plant Protection Society, Christchurch, New Zealand.
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