Invasive plant research trials
  • Last updated:
  • 04 Jan 2022

Council conducts research trials to monitor the effectiveness of control methods including:

  • herbicides
  • manual removal
  • mechanic controls 
  • new technologies such as solarisation

These research trials are important for the ongoing fight against invasive plants. Over time species may become resistant to a particular herbicide or new technology arises. Pest Plant officers aim to provide up to date and informed advice to assist landholders manage weeds on their properties. 

Council has been trialing the use of biodegradable Jute weed matting to suppress the growth of weedy Sporobolus sp. grasses along several roadsides

Target species

 Invasive Sporobolus sp. 

Schedule

 2016-ongoing

Location

 Conondale, Cambroon, Witta, Kenilworth and Verrierdale 

Protection methods

Suitable areas for trials were identified taking into consideration the amount of invasive Sporobolus grass present, safety of undertaking the trial and ability for the trial site to remain undisturbed. 

The Sporobolus grasses were brush-cut down to near ground level and then the Biodegradable Jute weed matting was laid out over the area. At one site larger clumps of Sporobolus grass were taken out before laying down the weed matting and native grasses were sown on top of the weed matting once it was showing signs of breaking down (after around 12-18 months). At the trial site in Verrierdale, lomandras (a drought tolerant native plant) were planted in the weed matting (at 50cm apart).  
Monitoring of this control method over several years proved that using the biodegradable weed matting (without any revegetation) was successful in initial suppression of the growth of invasive Sporobolus grass though overtime invasive Sporobolus spp. returned. 

At the trial site where larger clumps of Sporobolus were taken out initially and the area was reseeded with native grasses less invasive Sporobolus spp returned once the matting had broken down. 

The greatest success was the trial site at Verrierdale where no invasive Sporobolus spp. were present after 3 years and over 70 percent of Lomandra plants had survived. The success is likely due to the ability of Lomandra to suppress the regrowth of invasive Sporobolus once the weed matting had broken down.

Giant Rats Tail grass control trial using weed matting to suppress growth

 

Council has been trialing the use of solarisation to suppress the growth of weedy ground covers

Target species

Singapore daisy (Sphagneitcola trilobata)  

Schedule

2016-2019

Location

Conondale

Protection methods

Thick black builders plastic was laid out over the area and weighed down. The plastic was then left for 6 months. After 6 months the Singapore daisy had died and most had decomposed.  

Singapore daisy after solarisation 


Council assisted with the trial of solarisation to suppress the regrowth of running bamboo shoots after they had been cut.

Target Species

Running bamboo (Phylostachys spp.)  

Schedule

2018-2019

Location

Witta

Protection methods

Thick black builder’s plastic was laid out over the area of cut bamboo stumps and weighed down. The plastic was then left for 12 months. After this time there had been no regrowth apart from in the areas where the black plastic had broken and light was able to get in. The large starch reserves that bamboo contain mean that it requires significantly longer time without sunlight to ensure that regrowth does not occur. This site is still being monitored. 

Solarised bamboo stump