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Managing environmental weeds

Environmental weeds are a threat to our natural habitat in Knox. There are a range of ways you can manage and reduce their effect.

The impact of environmental weeds

Environmental weeds damage our habitat by:

  • overpowering and excluding native vegetation
  • preventing native species from regenerating
  • reducing habitat for native fauna
  • providing good conditions for introduced pests like rabbits and foxes
  • disrupting ecological and physical processes like fire regimes, hydrology and nutrient cycles
  • increasing fire risk.

Environmental weeds in Knox

Some plants have been determined by Council as environmental weeds.

Having these weeds on your property is an offence under Knox's Amenity Local Law

Download a list of environmental weeds

Noxious weeds

Some weeds are called ‘noxious’.

What that means is different depending on what state or territory you live in.

In Victoria, noxious weeds are declared under legislation (Catchment and Land Protection Act, 1994) and impact on natural areas, primary production or human health.

How weeds spread

Most environmental weeds threatening our bushland have spread from home gardens, tracks or roadsides.

Environmental weeds spread into bushland by:

  • having seeds spread by wind and water flow
  • birds eating the fruits or seeds
  • dumping garden rubbish
  • slashing or mowing.

They grow aggressively because they don't have many natural competitors or diseases to control them.

As a result, they harm our native vegetation and wildlife habitat.

Methods of removal

Here are some ways to remove environmental weeds.


This method suits small clusters, where other methods may disturb soil.

Manual removal includes:

  • hand pulling
  • digging using shovels, rakes, chisels, knives, forks or mattocks.

However, there are downsides to this method.

They include:

  • too much soil disturbance
  • spreading seeds, fruits and plant material.

Slashing and mowing

Slashing and mowing can reduce invasive species from spreading.

You can use mowers, brush cutters and tractor-mounted slashers, depending on the area. However, this can also spread seeds, bulbs and ripe fruits.

Treat these areas before the plants bear seeds or fruits.


Ringbarking suits trees and large shrubs that don't re-shoot when damaged.

Use an axe to cut away the bark and sapwood in a 5-10cm wide band below any branches around the lower trunk.

Make sure the cuts reach into the older inactive central wood of a tree or woody plant (heartwood).

Herbicide use

  • Cut and paint: Use this for climbers, creepers, shrubs and trees. Have your herbicide ready. Cut the plant as close and level to the ground so the herbicide doesn't run off. Apply undiluted herbicide to the outer rim of the stump within 30 seconds.
  • Drill and fill: Use this for shrubs and trees. Drill a 5cm deep hole at a 45-degree angle into the sapwood, right next to the base and below any branches. Inject herbicide into the hole. Repeat around the base of the plant with holes spaced at 3-5cm.
  • Frilling: Use this for larger shrubs and trees. Have your herbicide ready. Use a sharp knife or chisel to frill away the bark below any branches to expose the sapwood, no higher than half a metre from the base. Apply herbicide within 30 seconds. Repeat around the base 5-10cm apart.
  • Stem-scrape: Use this for suitable for vine species. Have your herbicide ready. Use a sharp knife to scrape back the bark 10-20cm. Apply the herbicide within 30 seconds using a paintbrush or dabber bottle.
  • Spraying: This method works for herbaceous and grass weeds. Make sure you follow the instructions on the label. Be extremely careful when you're using herbicide around plants you don't want to kill.


  • Surfactants: These are used to help herbicide get into the plant, particularly those with waxy leaves. Add a household detergent to the herbicide mix. This will help the herbicide stick to the foliage and get under the leaf surface.

Smothering or mulching

Cover an area of weeds with thick material that is hard to penetrate. You could use:

  • mulch
  • wet cardboard or newspaper with a layer of mulch on top.

How Council controls weeds

We use a range of methods to manage weeds on Council land, including mulching, steaming, hand weeding and selective herbicides for targeted weed species. At times, this includes the use of glyphosate-based herbicides such as Roundup.

These herbicides are widely used and sold in the community. Council follows advice and guidelines from government regulators to ensure a consistent focus on staff and community safety and environmental sensitivity. Methods such as hand weeding are preferred at sensitive sites, including playgrounds, kindergartens, preschools and school zones, but there are occasions when other methods are used in accordance with strict control measures.

More information on glyphosates can be found on the Australian Pesticides and Veterinary Medicines Authority website.


Weeds must be disposed of safely and in a way that limits further spread. You can compost seed-free plant material.

Do not put seed-heads, stem portions, bulbs and plants with aggressive root systems in the green waste bin.

These can spread through unscreened mulch.

Replanting after weed removal

An important part of managing environmental weeds is replacing them with plants which don't cause problems.

You can choose indigenous plant species grown from seed collected in our region (local provenance).

This creates habitat for native animals and birds and contributes to our local landscape.

Gardens for Wildlife (G4W)

Watching birds and animals interact in your newly established garden adds a special dimension to your life.

You'll attract local fauna just by planting local species. Find out more about Gardens for Wildlife.

Knox Environment Society Community Nursery

You can find Knox Environment Society Community Nursery (KES) next to Ferntree Gully Library on Burwood Highway, between Glenfern Road and Brenock Park Drive, Ferntree Gully.

Need help?

Contact us and we will come back to you.

Or call our Customer Service team on 9298 8000.

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