Coming from the UK, there are few plants that would cast such fear into the hearts of gardeners and homeowners more than “Japanese Knotweed”! In the UK it is actually illegal to allow it to grow on your property and land. If you are trying to get a mortgage and Japanese Knotweed is found at the property, chances are your mortgage will be denied! To dispose of Japanese Knotweed in the UK you need to make an appointment at a special disposal unit! So, I am from a land where this is serious stuff and the mere utterence of “Japanese Knotweed” is likely to instill panic and hysteria!
All that said….
I am not in the UK now. I am in France. In France….they generally do not see this plant as a problem. In fact, when I asked my local Mairie how I should dispose of it, she shrugged, said she’d never heard of it and suggested maybe just taking it to the tip in the local town.
When I first caught sight of it growing in our new home’s garden I certainly felt panic! I started seeing it everywhere popping up here and there, just single prongs but enough to raise my anxiety. Is the weather continued to get warmer we saw more…and then discovered that our neighbour appears to be cultivating the stuff! There is literally a forest of it on the plot of land behind our upper garden! So…. there is never NOT going to be Japanese Knotweed here! All I can do it remove it when I see it in our garden….and either take it to the tip….or….
I started to research whether there are any uses for Japanese Knotweed and what a surprise I found!
Cullinary Uses
You can eat Japanese Knotweed! Rumour has it, it tastes a little like Rhubarb (and to be honest the stems look a little like Rhubarb). I understand it has a sour tang from it and where rhubarb pairs naturally with red, ripe fruits, knotweed is much more at home with fall fruits like apples, pears, and grapes.
There are load of good recipes out there on the Internet – like these for example: https://foragerchef.com/japanese-knotweed/
Medicinal Uses
Japanese Knotweed exhibits antioxidant, anticancer, anti-inflammatory, antitumor, nerve protecting properties and many more. It may also help in weight loss and prevent and manage diabetes.
Antioxidant Activity: The extracts of this perennial herb are rich in antioxidants, mainly resveratrol. It has shown great benefits in aging, life span, and skin health. The resveratrol extracted from its roots is used as a dietary supplement for several health conditions, in medicine, and beauty products. Other antioxidant metabolites include quinines, stilbenes, flavonoids, catechols, phenolic acids, and tannins.
Weight Loss: The appreciable amount of resveratrol in the plant may help with weight loss, when its supplementation is coupled with physical activity and the right diet. Its mechanism for weight loss owes to its ability to boost metabolism and regulate estrogen levels. Boosting of metabolism augments processing of food consumed and hampers body fat storage, and regulating estrogen levels will help build muscles.
Antimicrobial Activity: Extracts of Japanese knotweed leaves found to contain components such as epicatechin, quercetin, and rutin that exhibit antimicrobial properties. Epicatechin is studied to impede the growth of Gram-positive bacteria but presented much lesser antifungal activity.
Cardiovascular Benefits: The resveratrol content of the herb may possess anticoagulant properties by reducing blood viscosity. It may also help in treating heart diseases like myocardial infarctions by preventing blood clots and embolisms. Resveratrol can also be beneficial in aspirin resistance by down-turning platelet aggregation.
Phytoestrogen Activity: Phytoestrogens are foods that produce similar effects of the hormone estrogen when ingested in the body. The resveratrol present in the plant acts as anagonist to receptors of estrogen and inhibits estradiol. It also aids in muscle building by regulating estrogen levels.
Lipid-Lowering Effects: Animal studies reported that bioactive components, namely polydatin and emodin aid in lowering lipid levels and may also have liver-protective effects.
Japanese knotweed is rich in several vitamins and essential nutrients that have health benefits; however, it’s wise to seek medical advice before making Japanese knotweed part of your diet or supplements routine. Here are three types of nutrients you will find in the plant:
Minerals: Potassium and magnesium are two essential minerals you can find in Japanese knotweed. These minerals work with calcium in your body to build strong bones and improve joint functionality.
Resveratrol: Japanese knotweed is an excellent source of resveratrol (polygonum cuspidatum), and in many parts of the world, people harvest the plant specifically for resveratrol extraction. The same compound is also in grapes and red wine. Although studies have so far been inconclusive, scientists continue to study whether resveratrol might have a positive effect on preventing Alzheimer’s disease, cardiovascular disease (heart disease), and cancer; on treating ailments such as Lyme disease; and on helping to regulate blood pressure.
Vitamins: Japanese knotweed contains several essential vitamins, including vitamin A and vitamin C. Both of these nutrients assist your body in maintaining a healthy immune system against disease and infection.
I may not be thrilled at the idea of having Japanese Knotweed in our garden but hey….there appears to be some real positives I can take from it 🙂
Update 08/08/2023: My first tinctures are ready!
I soaked the Japanese Knotweed root in alcohol (high proof vodka) for about 2 months, gently shaking ocassionally. I then passed it through a coffee filter and decanted into brown-glassed tincture bottles.