Weed management at Tarcutta

Michelle Stook
Published 15 Sep 2020 
by Stephen Gye 
about  Tarcutta Hills Reserve  
Hand weeding Paterson’s Curse using a chipping tool (foreground) and spot burning using a flame weeder (background).<br/> Hand weeding Paterson’s Curse using a chipping tool (foreground) and spot burning using a flame weeder (background).
Hand weeding thistles.<br/> Hand weeding thistles.
Burning of Paterson’s Curse rosette with flame weeder.<br/> Burning of Paterson’s Curse rosette with flame weeder.
Outside the exclusion site.<br/> Outside the exclusion site.
Inside the exclusion zone.<br/> Inside the exclusion zone.

Recently my wife Jane and I were assigned to help at a weeding bee on Tarcutta Hills Reserve, which is 50km south east of Wagga Wagga in New South Wales.

Our task was to deal with two weed species – Paterson’s Curse (echium plantagineum) and various thistles, primarily using hand weeding techniques but also trialling spot burning of small individual plants using a flame weeder. Bush Heritage was trialling the effectiveness of hand weeding compared with spot spraying with herbicide (to reduce herbicide use if possible).

Infestations of Paterson’s Curse were treated using three hand weeding techniques – hand pulling, crowning with a crowning knife, and chipping using light short handle chipping tools.

Given the plant is an 'annual' the intention was to prevent flowering and subsequent seeding in the current growing season. These techniques – particularly the crowning and chipping – assume the plant won't regrow once the root crown and rosette have been removed.

Where the ground was soft, hand pulling with a twisting motion worked to remove entire plants, including their tap roots (sometimes over 10cm long). However, in harder ground, the root often snapped near the top. Chipping invariably left a significant part of the root in the ground unless the plant was completely dug out. Crowning with a knife may or may not leave the root intact depending on how much care was taken to avoid cutting the root. All three methods successfully removed the ground rosette and any leaf growth.

Damon Basset, the Tarcutta Field Officer advised that whilst this approach is hard work in the beginning, the aim is to:

  • break the seed cycle and thereby reduce our workload over time
  • allow native plant species to regenerate
  • reduce our herbicide use without compromising our ecological goals
  • change and build soil health.

During our trip we were able to visit an exclosure site in the southern part of the reserve that's been erected to give the native species a protected chance for growth.

There are some areas of the reserve we observed that had been subjected to extensive clearing, presumably for sheep grazing, which would have occurred prior to Bush Heritage ownership. There's little understorey there, as it's an open woodland with a sparse shrub layer and eucalypt regrowth is scant in some areas.

The photos show the clear difference in growth of grasses and shrubs inside the exclosure compared to the unfenced area.

We believe that this is necessary to promote regrowth in key areas and Damon advised that Bush Heritage have currently fenced 30 nodes in the northern part of the reserve with the results being very promising so far.

It was a wonderful opportunity for us to finally get out into the field this year and visit a reserve closer to home and to contribute to the ongoing conservation goals of the property.

Hand weeding Paterson’s Curse using a chipping tool (foreground) and spot burning using a flame weeder (background).<br/> Hand weeding Paterson’s Curse using a chipping tool (foreground) and spot burning using a flame weeder (background).
Hand weeding thistles.<br/> Hand weeding thistles.
Burning of Paterson’s Curse rosette with flame weeder.<br/> Burning of Paterson’s Curse rosette with flame weeder.
Outside the exclusion site.<br/> Outside the exclusion site.
Inside the exclusion zone.<br/> Inside the exclusion zone.