We got this question.

recommended either Glyphosate or GA200 for general weed control in our home garden. For use under hedging and general gardens with a mix of planting. Which of the two products would you recommend please? 


The answer depends upon a few key points.

Both are what you call non-selective so will kill most things.  Grass, weeds etc.  The major difference is the mode of action.

Glyphosate 540

Rainbow & Brown Glyphosate 540 (or Glyphosate 360 or even the soluble high strength granular Granny are non-selective herbicides and although in many cases glyphosate can be used around trees and shrubs great care should be taken.  These are known as systemic herbicides which means they will translocate through the symplast of the weed.  The have little, if any residual activity which makes them ideal for spraying out prior to replanting or seed bed preparation.

  • Rainbow & Brown Glyphosate 540 will translocate through the plant down to the roots.
  • as a result if sprayed onto a shrub or tree you want to keep even a little overspray on this can kill the whole plant.
  • It is though deactivated in the soil so there are no residuals so quite safe to plant after the weeds are dead.
  • Glyphosate is relatively cheap.
  • Glyphosate is not so good on clover.

GA200 (Glufosinate Ammonium 200g/L)

Rainbow & Brown GA200 (glufosinate ammonium 200g/L) works by inhibiting the plant enzyme acetolactate synthase (ALS) which in turn causes a build up of ammonia in the plant to levels that are toxic to the plant.  GA200 is considered to be a contact herbicide with little or no herbicide translocation or movement through the plant.  As a result perennial weeds will often regrow.  GA200 is a reasonably good alternative to paraquat and is much less toxic.  

  • Rainbow & Brown GA200 a contact herbicide so this means it will only kill the plants that are well-sprayed.
  • This means inadvertent spray on a non-target plant probably won’t kill it unless you covered the whole plant.  You might just lose a branch or some leaves.
  • Because it is mainly contact with little translocation weeds are more likely to need more frequent re-spraying
  • GA200 is quite a bit more expensive than glyphosate.
  • It is though used extensively in vineyards, orchards etc. because of the low risk to vines and trees.
  • GA200 is more effective in killing clover.
  • GA200 works poorly in low temperatures.
  • GA200 is non-volatile

This is a quick summary of many of the key differences and whichever product you use will vary depending upon your needs.