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WeedWise
KHAKI WEED
Alternanthera pungens
Description & life cycle
Photographs are courtesy of Dr Sheldon Navie
Khaki Weed is found throughout many parts of Australia, both coastal and inland, but is most common in eastern Queensland and NSW. It has
a long-lived root system, but its above ground growth is short-lived and occurs mainly during summer and autumn. It is primarily is a weed of
public amenity areas such as lawns, footpaths, playing fields and parks, where its prickly burrs are a nuisance to users of these areas.
This native of South America develops a deep, carrot-like, taproot up to 12mm thick and 100mm long. It remains dormant in the soil during
winter, but produces new growth each spring following rain. Seedlings also emerge after spring and summer rains, germinating from a bank of
long-lived seeds stored in the soil.
The oval-shaped leaves are up to 5 cm long with pointed tips, and are borne in unequal pairs (i.e. one is normally large than the other). Its
branching stems spread out across the ground surface, producing roots at their joints and forming a thick mat. They are often reddish in colour
and are covered with short, soft hairs.
Small greenish-yellow flowers are produced in dense clusters in the forks of the leaves from late spring through to autumn. As the flowers
mature they become chaffy in appearance and are surrounded by fine, straw-coloured, sharply-pointed prickles. These prickle bearing burrs can
become quite troublesome, as they are able to pierce the skin of picnickers and people walking around in bare feet.
Khaki Weed produces large quantities of seed in summer and autumn, which are easily spread when the prickly burrs become attached to
animals, shoes, clothing and motor vehicle tyres. It can also reproduce and disperse to new areas when fragments of its rooted stems become
dislodged by mowers or graders. In addition, seeds and stem fragments can also be spread in lawn clippings or on slashers.
Key features
> Khaki Weed is common in parks, along footpaths, on ovals and in other public open spaces.
> It forms a thick mat very low to the ground, making it impossible to be mown out.
> The sharp burrs can be a real nuisance during summer and autumn.
> Its deep taproot makes it difficult to control.
Control
1. Small infestations can be dug out or removed by hand (with gloves), prior to seeding.
2. Large infestations in ovals and other grassed areas require the application of a selective herbicide, which does not damage the particular grass
species present. Khaki Weed seedlings are susceptible to a range of selective herbicide formulations. To achieve the best results, Technigro recommends that herbicide applications be made while the weeds are young and actively growing, and prior to the plant producing seed.
3. The use of a pre-emergent herbicide should also be considered in situations where Khaki Weed has built up significant populations of seed in the
soil. Using such herbicides with the correct timing can break the plant’s life cycle, by preventing germination from occurring.
Your Provider of Vegetation Management Solutions
[email protected]
T: 1800 678 611 www.technigro.com.au