Japanese knotweed (Fallopia Japonica), has earned itself a negative reputation in the UK.

Japanese knotweed is regarded as being the UK’s most aggressive and destructive plant, spreading across the UK and causing havoc to those unfortunate enough to own property in its way.  It’s undoubtedly a nuisance to have on your land. It causes damage to property, it’s expensive to get rid of, and can potentially devalue your property.

Because of this reputation we decided to carry out research to see if Japanese knotweed has a good side to it.

Can Japanese knotweed be used for biomass?

Could knotweed be used for biomass, to heat our homes? It is a possibility but the stems and leaves are not heavy and therefore have little calorific value. You might be surprised to know that the stems, canes and leaves of knotweed are 90% water. We therefore doubt growing Japanese knotweed as biomass on a large scale would be cost effective once the expense of regulatory compliance is taken into account.

Does Japanese knotweed have any medicinal purpose?

Does Japanese knotweed have any medicinal value? You may have heard of resveratrol, found in both Japanese knotweed and grapes, which is claimed to have anti-ageing qualities, and sold in capsules in health food shops. The underground part of the plant i.e. the root and rhizome system, has already been used as medicine in China for thousands of years, mainly treating Lyme disease, cough, joint pain, chronic bronchitis, jaundice, amenorrhea, hypertension, and so on.  It’s dried and ground up into a powder called Hu Zhang. But it comes with many warnings, because if you take too much, it is toxic, as summarised by the following internet post:

“If you are going to consume Japanese knotweed use caution, only take a teaspoon, my boyfriend with chronic lymes ate a finger-sized piece of fresh root and had to go to the hospital after vomiting blood. It is best to dry it out, make it into powder, and only take a teaspoon!”

We’d add to that point that a lot of knotweed in the UK will have previously been treated with potentially harmful herbicides, which might be what made the boyfriend vomit blood.

We thought it might be interesting to make some Hu Zhang from the tonnes of knotweed we remove every year from soil using our Xtract™ method, as shown in the photo above.

We’re not sure of the best way to administer the possible medicine, and we’ve had no takers so far in our office. We’re all relatively young and healthy at Environet so perhaps no one thinks it’s worth the risk!

Get in touch today if you have any queries about what to do if you spot Japanese knotweed.