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For knotweed

Brush cutters and Japanese knotweed: what to use and what to avoid

Knotweed grows in dense, hollow-caned stands — and every fragment can regrow. Before you pick a machine, understand why cutting needs care and how to handle the waste.

By · Updated · first published

In short:Japanese knotweed can regrow from small fragments of stem and rhizome, so strimming or flailing it with line spreads it and is best avoided. If you cut canes — for access or as part of a treatment programme — use a metal blade to cut cleanly, collect every piece, and treat the waste as controlled waste. Cutting alone won't kill it. Powerful bike-handle machines with harnesses, such as the Stihl FS 131, Makita EM4351UH, Honda UMK 435 or Stiga BC 545 B, cut canes cleanly; the Einhell GC-BC 52 and Fuxtec FX-MS152 are budget options.

Our picks, ranked

  1. 1
    Stihl FS 131 semi-pro petrol brush cutter 36cc 4-MIX brambles heavy use
    Semi-pro

    STIHL · 36.3 cc · 4-MIX

    Stihl FS 131

    For tough land and heavy use: a 36.3 cc, 1.4 kW 4-MIX brush cutter with a bike handle, 5.8 kg and a 420 mm cut — Stihl's semi-pro petrol benchmark.

    8.7/10
    Read the review
  2. 2
    Makita EM4351UH 43cc 4-stroke MM4 professional petrol brush cutter bike handle
    Pro 4-stroke

    MAKITA · 43 cc · 4-stroke MM4

    Makita EM4351UH

    A professional 43 cc MM4 four-stroke petrol brush cutter, 1.5 kW, with handle vibration of 2.1–2.2 m/s² — mix-free power for long working days.

    8.4/10
    Read the review
  3. 3
    Honda UMK 435 GX35 4-stroke petrol brush cutter with harness and blade
    Pro 4-stroke

    HONDA · 35 cc · GX35 4-stroke

    Honda UMK 435 UE

    A bigger, tougher Honda 4-stroke: the 35 cc GX35 gives 1.0 kW for bramble clearing on a bike handle with a double harness, still without mixing fuel.

    8.6/10
    Read the review
  4. 4
    Stiga BC 545 B 42cc 2-stroke petrol brush cutter 3-tooth blade double harness
    Complete 42cc

    STIGA · 42.7 cc · 2-stroke

    Stiga BC 545 B

    A strong 42.7 cc petrol brush cutter supplied complete with a 3-tooth blade, Tap&Go head and double harness — ready for tough, regular clearing.

    8.0/10
    Read the review
  5. 5
    Einhell GC-BC 52 I AS 52cc 2-stroke petrol brush cutter with 3-tooth blade
    Big value 52cc

    EINHELL · 51.7 cc · 2-stroke

    Einhell GC-BC 52 I AS

    A powerful 51.7 cc, 1.5 kW petrol brush cutter with a split shaft, 3-tooth blade, twin-line head and carrying strap included — a lot of clearing power for the money.

    7.8/10
    Read the review
  6. 6
    Fuxtec FX-MS152 52cc 2-stroke petrol brush cutter 3-tooth steel blade harness
    Value 52cc

    FUXTEC · 52 cc · 2-stroke

    Fuxtec FX-MS152

    A 52 cc, 2.95 hp petrol brush cutter with a metal blade, line head and padded strap included — huge cutting capability for tough, overgrown land.

    8.0/10
    Read the review

Cut carefully, or not at all

Japanese knotweed regrows from tiny pieces of stem and rhizome. That makes the usual brush-cutter approach — strimming or shredding a stand — counterproductive: you spread fragments across the site. Many people are best served by calling a knotweed specialist. If you need to cut canes, do it in a way that keeps fragments to a minimum.

If you do cut: blade, not line

Use a metal brush blade to make clean cuts low on the cane, rather than line or a flail that shreds. Lay a sheet down to catch material, cut stand by stand, and bag every piece as you go. Clean the machine, boots and tools on site before leaving, so fragments don’t travel.

Machines with the torque for canes

Mature canes are hollow but tough, so a powerful bike-handle machine with a harness cuts cleanly without juddering:

  • Stihl FS 131 — 1.4 kW 4-MIX, strong low-speed torque; 5.8 kg without guard or tool.
  • Makita EM4351UH — 43 cc MM4, 1.5 kW, very low vibration.
  • Honda UMK 435 UE — GX35, bike handle, double harness.
  • Stiga BC 545 B — 1.25 kW, 3T blade and double harness in the box.
  • Einhell GC-BC 52 — 51.7 cc, 1.5 kW, 25.5 cm 3-tooth blade.
  • Fuxtec FX-MS152 — 52 cc, 2.95 hp, metal brush blade.

Waste and the law

Knotweed waste is controlled waste, and allowing knotweed to spread into the wild can be an offence. Don’t compost it, put it in council green bins or move soil containing it without the right arrangements. Rules and guidance differ across the UK nations, so check the current official advice before you start.

For other invasive canes, see the best brush cutters for bamboo; for general clearing, overgrown land.

Our picks at a glance

ModelTypeEngine / powerWeightRating
Stihl FS 131 Petrol 36.3 cc · 4-MIX 5.8 kg (without guard and cutting tool) 8.7 / 10
Makita EM4351UH Petrol 43 cc · 4-stroke MM4 8.5–8.6 kg (retailers) 8.4 / 10
Honda UMK 435 UE Petrol 35 cc · GX35 4-stroke About 7.5 kg dry (retailers: 7.53–7.6 kg) 8.6 / 10
Stiga BC 545 B Petrol 42.7 cc · 2-stroke — 8 / 10
Einhell GC-BC 52 I AS Petrol 51.7 cc · 2-stroke 8.5 kg (listing) 7.8 / 10
Fuxtec FX-MS152 Petrol 52 cc · 2-stroke — 8 / 10

Weights are as stated by the maker, UK retailers or Amazon, so some include a battery or cutting gear and others don't — see each review for details.

Compare our picks head to head

Frequently asked questions

Should I strim Japanese knotweed?

No. Line shreds canes into fragments that can regrow wherever they land. If you must cut canes, use a metal blade to make clean cuts, and collect everything.

What do I do with the cuttings?

Knotweed waste is controlled waste: don't put it in your green bin, compost it or fly-tip it. Bag it securely and use a licensed waste carrier or a site that accepts it, or follow official guidance on on-site disposal. Check the current rules for where you live.

Will cutting get rid of knotweed?

No — the rhizomes survive underground. Cutting can be part of a treatment plan, but lasting control needs herbicide treatment over several seasons or excavation, usually by a specialist. It's also an offence to cause it to spread into the wild.