Weeds after floods

Things might get sticky

Tablelands Telegraph – December 2021

Marita Sydes, Senior Land Services Officer, Weed Action Program

The potential spread of the emerging weed sticky nightshade (Solanum sisymbriifolium) with flood waters in the region is a real risk.

Over the last few years sticky nightshade has increasing in distribution in the upper Belubula catchment, often establishing in the river channel itself. In these areas sticky nightshade readily germinates from the seed under established plants and plants can easily establish from broken root fragments.

If seed or root fragments were carried down the river with flood water, then there is a real chance that sticky nightshade will establish further down the Belubula catchment (downstream from Canowindra) or even in the Lachlan River corridor downstream of the Belubula River junction.

We are encouraging landholders along the Belubula River and the Lachlan River downstream of the junction with the Belubua River to be on the lookout for sticky nightshade and control any infestations that they may find.

Early control of isolated plants of sticky nightshade is critical in stopping the spread of this invasive weed. Information on control of sticky nightshade can be found on NSW WeedWise or by contacting your local councils Weed Biosecurity Officer.

Getting on top of weeds after flood

Flood waters can carry and introduce new weed species onto paddocks, banks, and along roadsides. With the flooding that has been seen in the region recently now is the time to start to watch out for new weeds.

  • Monitor areas inundated by flood water for the next 12 months at least. Some weeds may not be visible until a year or two after the flood. If you find weeds that you don’t know what they are, get help with identification early before they spread further.
  • Weed propagules (seed or vegetative parts) can be readily dispersed in flood waters. For example, Chilean Needle Grass was seeding at the time of the floods and has the potential to be spread by water.
  • Weed seeds can easily attach to vehicles and equipment in the muddy conditions after a flood. Ensure that vehicles and equipment, including those of contractors and advisors, are clean and free of weeds before entering or leaving your property. Consider providing a designated wash down area for this purpose.
  • Pastures or crops may be impacted by the flood – this may reduce ground cover and allow weeds to more readily grow and establish.
  • If you moved stock to higher ground or to different properties during the flood be careful not to spread weeds from these holding areas when you return stock to the flood impacted areas.

Information on the identification and control of weeds in your region can be found on NSW WeedWise or by contacting your local councils Weed Biosecurity Officer.

Image top – Sticky nightshade growing along Belubula River, Ed Hogan

Image bottom – Sticky nightshade root, A Fletcher

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