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NQ DRY TROPICS WEED FREE
SIAM WEED
Chromolaena odorata
DESCRIPTION
Siam weed is a perennial that grows as a dense tangling bush up to 3 metres ; however it can climb up trees to 20 metres . This plant looks very similar to lantana when not flowering . It often occurs amongst thickets of lantana . Stem and roots several smooth , round and brittle stems develop from the crown . The root system is shallow and there is an enlargement at the junction of the stem and root . Leaves are triangular , soft , green and hairy , with a distinctive three vein pitchfork pattern . New leaf growth can be purple . Flowers are pale lilac or white which turn a darker pink when mature . It flowers in autumn , winter and spring . Seeds are numerous with white hairs and tiny sticky barbs . Habitat it is suited to highly productive land types and invades rainforests , as well as creek and riverbank vegetation . Weed characteristics it can out-compete other crops and vegetation because of its growth rate . It is poisonous to cattle and may also cause skin complaints and asthma in allergy prone people . Dispersal Seeds can be transported by wind and water or by sticking to clothing , foot wear , animals , vehicles and machinery .
SIAM WEED
SHRUBS
BIOSECURITY MATTER
Restricted . This species is Category 3 Restricted matter under Queensland Legislation .
HOW TO ACT
New infestations must be reported to Biosecurity Queensland on 13 25 23 . The plants must be identified and removed by approved officers and have their locations recorded prior to removal . All control methods should target plants before they set seed . Physical removal of basal / root ball is effective for isolated and small infestations with removal of all plant material important , or chemical control with a broad leaf selective herbicide . It is essential to mark the site for follow up monitoring and control of emergent growth .