Triffid weed or Paraffin bush - Chromolaena odorata

This invasive alien species is present in the Mount Moreland Conservation area

 

Chromolaena odorata commonly known as Chromolaena, Paraffin bush or triffid weed is a flowering shrub in the daisy family, Asteraceae it is native to North America, from Florida and Texas to Mexico and the Caribbean.

 


Triffid weed or Paraffin bush - Chromolaena odorata

Chromolaena odorata is a scrambling, sparsely hairy shrub growing up to four meters or higher often forming dense thickets. The stems are opposite with wide spreading-branches they have light green, ovate to tri-angular leaves, with three conspicuous veins originating in the base of the leaf. The plant exudes a strong smell of paraffin when crushed. It produces masses of white daisy like flowers during the winter months when it is most easily recognised and controlled.  

 

Chromolaena is one of the world’s worst weeds.

Chromolaena odorata is recognised as one of the world’s worst weeds which is very widely distributed and is still expanding its range due to its very effective long-distance wind dispersal of seed. It is viewed as a major environmental weed. Chromolaena odorata has been reported to be the most problematic invasive species within protected rainforests in Africa. In South Africa it is regarded as a dangerous invader. Chromolaena odorata germinates readily, grows rapidly and produces vast quantities of wind dispersed seeds it is highly competitive. 

 

 

Control measures  

The control of Chromolaena is very easily achieved but it is an ongoing process as new seeds continue to blow in from distant infestations. The most effective means of eradication and control for small infestations is to remove the entire plant including the roots mechanically such as by hand weeding or digging and uprooting using a mattock or spade. For larger infestations the best method is to use machinery such as brush cutters or heavy duty  mowers to remove and mulch the top growth of the plant followed as soon as is possible by an application of  a herbicide containing glyphosate or triclopyr mixed at the rate of 1% with water which is applied to the cut stump.  

For small infestations spot spraying with a herbicide containing glyphosate or triclopyr mixed at the rate of 1% with water is also very effective but care must be taken not to damage no target plants.  

 

Regular follow up to check for new seedlings and re-growth is important in the control of Paraffin weed. The most important rule in the control of Chromolaena odorata is to not allow any plants occurring on your property to ever be given the opportunity to seed. The removal of any plants that have been overlooked during the year is easily achieved during the winter months when the plants are in flower because at this time they are very easily located and removed. 

 

Michael Hickman 

17.04.12