Published July 2, 2010

Landholders in the Piambong area - it’s not too late to get involved in Watershed’s Serrated Tussock Project.

The project is now offering landholders on-farm vegetation surveys with our “grazier-botanist” Christine McRae. Working with landholders, we’re aiming to map out the density and distribution of serrated tussock (if present), along with particular desirable species that are good competitors against the serrated tussock seedlings.

As adult serrated tussock plants can shed 80,000-120,000 seeds per plant per year, encouraging a strong, active ground cover of other perennial species that compete for nutrients and moisture when tussock seeds are trying to germinate is a major part of reducing spread of this weed.

Some native grass species are actively growing and provide good competition at the time of year when there are newly germinated tussock seedlings. You may not be able to give up the spray bottle completely, but encouraging and managing for these desirable species might be the difference between spot spraying/chipping a few plants a year as opposed to spraying 1000’s of tussock plants.

A number of on-farm surveys have already been conducted in the Piambong area and they have revealed variable levels of density and distribution of tussock; slowly spreading in some areas and retracting in others. We’re recording landholder ‘tips of the trade’ and it has been great to hear how different landholders approach chemical control (the most familiar tool for weeds), grazing, groundcover, soil fertility and pasture species management.

One landholder preferred to use glyphosate because he can see the effect within a week. He was pretty particular about the size of spray pattern and spot-sprays primarily with a hand-held spray bottle that allows him to hit only the tussock, not the surrounding desirable plants.

The other main chemical used on serrated tussock is called flupropanate. This is a slower acting, residual herbicide that binds onto the soil particles where it’s sprayed. It does not leach out of the soil, but is broken down over time by soil biology (chemical activity can last up to 2-3 years, but generally starts to break down within a year). Existing serrated tussock plants or germinating seedlings are poisoned by the chemical which is taken up through roots. These plants die in the following 2-12 months. Some native pasture species are tolerant of flupropanate (i.e. it may affect their growth somewhat, but won’t kill them) including Red Grass and Kangaroo Grass. Other species are susceptible, including Weeping grass (Microlaena), Wallaby Grass and legumes.

During the surveys so far we’ve found pastures dominated by Red Grass in some areas, and Microlaena in others.
Contact Thea at Watershed if you’d like more information about taking part in an on-farm vegetation survey.

This project has been made possible by the Central West Catchment Management Authority “Reducing the Impact of Weeds of National Significance” program.