Weed Control Along Fence Lines — Chemical vs Mechanical

Weeds along fence lines are more than an eyesore. They push against mesh and loosen it, create a fire hazard in summer, harbour vermin, seed into your paddocks, and make fence inspections difficult because you can't see the fence. Keeping fence lines clean is basic property maintenance, but the question is: spray or slash?

THE CASE FOR CHEMICAL CONTROL

Spraying fence lines with herbicide (typically glyphosate or a residual mix) is the most common approach across the Central West. Here's why it's popular:

Thoroughness: Spray kills weeds right up to and under the mesh. Slashing can't get between the wires or under the bottom wire where weeds grow thickest.

Duration: A well-timed spray with a residual herbicide keeps the fence line clean for 3-6 months. Slashing might need repeating every 6-8 weeks in a good growing season.

Speed: A farmer with a quad bike and spray unit can do several kilometres of fence line in a morning. The same distance with a slasher takes significantly longer.

Cost: Herbicide for fence lines is relatively cheap — a 20L drum of generic glyphosate at farm supply prices covers a lot of fence. Slashing costs fuel, time, and equipment maintenance.

Practical method: Spray a 1-1.5m strip along each side of the fence using a boom sprayer (for accessible areas) or a handgun off a 12V spray unit mounted on a quad or ute. Spot-spray woody weeds and problem species with a stronger mix.

Timing: In the Central West, the best time to spray fence lines is autumn (March-April) when summer weeds are actively growing and winter weeds are germinating. A second spray in spring catches anything that survived.

THE CASE FOR MECHANICAL CONTROL

Slashing, whipper-snipping, or mulching has its own advantages:

No chemical residue: If you're running an organic operation or have chemical restrictions (near waterways, neighbour concerns), mechanical control is the only option.

Soil preservation: Bare soil along fence lines erodes, particularly on slopes. Slashing leaves some groundcover that protects the soil. A chemically stripped fence line on sloping country can become an erosion gully.

Immediate result: Slashing gives you a tidy fence line the same day. Chemical spray takes 7-14 days to show full results (longer for tougher weeds).

No off-target damage: Spray drift can damage desirable trees, crops, or neighbour's pastures along the fence line. Slashing has zero off-target risk.

Practical method: A tractor-mounted slasher or a ride-on mower handles the paddock side of the fence. A brushcutter/whipper-snipper handles the fence side and the strip under the mesh. Some producers use a special fence-line mulcher that reaches under the bottom wire.

THE HYBRID APPROACH (OUR RECOMMENDATION)

Most savvy producers in the Central West use a combination:

Chemical: Spray a narrow strip (500mm) right along the base of the fence on both sides. This kills the weeds that grow through the mesh, under the bottom wire, and around picket bases — the stuff you can't reach mechanically. Use a shielded spray nozzle to minimise drift.

Mechanical: Slash or mulch the broader strip (1-2m) on each side of the fence. This keeps the area tidy, maintains some groundcover to prevent erosion, and gives you clear access for fence inspections and repairs.

This approach gives you the best of both worlds: clean mesh and wire (chemical), good visibility (mechanical), and maintained groundcover (slash rather than bare earth).

SPECIFIC WEED CHALLENGES ON FENCE LINES

Blackberry: A serious problem along fence lines in the Central West ranges and higher-rainfall areas. Blackberry grows through mesh and makes fence maintenance nearly impossible. Chemical control (glyphosate + metsulfuron mix, or triclopyr for resistant populations) is essentially the only practical option. Mechanical removal is temporary — it grows back from the roots.

Serrated tussock: A declared noxious weed across the Central Tablelands. Must be controlled on fence lines (and everywhere else). Flupropanate is the standard chemical treatment. Mechanical control doesn't work — it just spreads the seed.

Patterson's curse: Common across the Central West in spring. Easily controlled with broadleaf herbicides or slashing before flowering.

African lovegrass: Increasingly common and hard to control. Burns hot in summer, creating a fire risk along fence lines. Slashing before seed set helps reduce spread. Chemical options exist but are expensive over large areas.

Woody regrowth: Saplings and suckers along fence lines (particularly eucalypt regrowth on cleared land) will eventually damage mesh. Cut and paint with herbicide is the most effective method — cut the stem and immediately apply concentrated glyphosate or picloram to the cut surface.

HOW WEED CONTROL PROTECTS YOUR FENCING INVESTMENT

Clean fence lines mean:

• You can see damage and fix it promptly
• Fire risk is reduced (important for protecting fence posts and mesh from heat damage)
• Mesh lasts longer (weeds trap moisture against wire, accelerating corrosion)
• Electric fences actually work (vegetation earthing out electric wires is the number one reason electric fences fail)
• Stock pressure on fences is reduced (weeds attract stock to the fence line)

A few hours of fence line maintenance each season saves thousands in premature fence replacement. Look after the fence line and the fence looks after itself.

For all your fencing materials and maintenance supplies, visit us at 76 Astill Drive, Orange, or call 0434 093 077.