Glyphosate Weed Killer
Glyphosate is a broad spectrum systematic total weedkiller; it is a non-selective herbicide so will kill most plants. As it inhibits a plant enzyme which is needed for plant growth it is only effective on plants which are actively growing and not pre-emergence plants. It was first brought to the market as Roundup by Monsanto in the 1970's and is one of the most popular total weed killers.
Despite numerous pieces of bad press, Glyphosate has been proven safe time and time again. It was re-approved for a further 5 years in the UK in 2018. At present, there are no viable alternatives that deliver as good results for the cost.