Properties of a plant pest

The current bane of the British countryside is Japanese knotweed. It is such a problem that numerous companies offer eradication services and the Environment Agency has a substantial section of its website devoted to managing the weed.

Merlin recalls dealing with a rather less vicious garden pest after moving into a house newly built on former vacant land. This was couch grass (Elymus repens, formerly Agropyron repens), which grew in large clumps all over the property. Merlin heaved on one clump and up came about six or seven others, all interconnected by white, string-like rhizomes.

For many years the recommended treatment for couch grass has been glyphosate, a constituent of many weedkiller products. Always the environmentalist, Merlin resisted this easy solution and set about eradicating the offending species by pulling up the clumps.

This took several years, but proved that one did not need toxic chemicals to eradicate a weed, just patience and much effort.

Couch grass was at one time used medicinally. Culpeper, in his ‘Complete herbal’, refers to its nuisance value: “It grows commonly through this land in divers ploughed grounds to the no small trouble of the husbandman.”

Culpeper recommends bruising the roots (presumably he means the rhizomes) and boiling them in white wine, then drinking the decoction. This is said to open all obstructions of the liver and gall bladder.

Culpeper also maintains that the roots “bruised and applied, do consolidate wounds”. Does this mean that they have a styptic or coagulant effect?

In a quick internet search, Merlin found the following indications on one website:

• irrigant
• demulcent
• antimicrobial
• cystitis
• urethritis
• prostatitis
• urinary tract infections
• renal gravel
• upper respiratory disorders
• gout
• rheumatism
• cough
• cirrhosis
• tumours
• cancer

However, neither this, nor other websites gave any indication of possible toxicity from couch grass preparations.

Bearing in mind that most drugs (including herbal ones) can be regarded as toxic chemicals with therapeutic side-effects, one should exercise caution. I would be interested to know if the medicinal or other properties of couch grass have ever been investigated scientifically?