I’ve decided to write a piece on Japanese knotweed ( Fallopia japonica ) which is a wild edible that I actively use in various recipes ,
I’ve had various conversations with other foragers and conservationists regarding donkey rhubarb ‘ as we called it as children, many of them quite passionate with really good arguments on both sides of the fence but the one thing that I’ve noticed from both sides is the lack of actual information people are aware of is staggering , some of the most common comments made are ,
“. it’s an invasive species so it’s is terrible in any situation “
” it can reproduce from a piece the size of a pin head ”
My aim is to just cover some information that should allow any self aware and respectful forager to utilise this edible without risk and also reducing the problem itself and to share a simple recipe I use .
First we should cover the risk , the first one being that by irresponsible foraging we will spread the plant to a new location ,this holds more than just the ecological implications but actually is illegal and the Wildlife and Countryside Act 1981 states that
it is an offence to “plant or otherwise cause to grow in the wild”
any plant listed in Schedule nine,
And that comes with a possible fine of up to £5000 or six months in prison or both
So that in basic terms means that if you knowingly plant knotweed or disregard knotweed waste in a manor that leads to it’s spread you are guilty of the above charge .
So what can we do as foragers to be completely sure we are not making a bad situation worse whilst utilising this edible ,
Firstly is a rule any conscious forager abides by only take what you are in need of as there is no real way to legally or safely dispose of any excess .
Next is preparation so when harvesting allow time to trim and prepare your pickings at the already infected site this way you only ever take away needed items and peelings and trimmings never leave the site so there is little risk of further spread .
I then place any harvest in a zip seal bag to take home and this Is then destroyed after use not using my normal foraging baskets or bags stops any accidents .
The next thing I always do which gets some good looks is to put a couple of old carrier bags on my boots when entering the patch and removing them upon leaving it , ( it is common knowledge that knotweed can re grow from a small piece of the plant it is more likely from the crown or root but is possible from the new growth stem , in greenhouse testing the plant has regenerated from pieces about ten millimetres cubed or larger not small specks of the plant ).
Also seeds are not an issue as all plants recorded in the uk are female and unable to pollinate so all and any spread that has occurred has been from rhizomes .
The next and biggest risk to us as foragers is man made it is in fact the use of chemical pesticides in some undereducated attempt to resolve the problem it’s a sad fact that the money spent trying to resolve the invasion of Fallopia japonica is only a small percentage of the £166 million that the NNSS has declared approximately has been spent is used on researching a viable control method other than spraying harmful chemicals all over the site , when a American research paper has found that bog standard coffee has more positive results than the fungal avenue that is currently be explored in the uk ,
Coffee contains a multitude of stimulants and other chemicals. One of these compounds is dimethyl-xanthine, which has been shown to stop the production of cytokinin, which is needed for root growth and cell development. It is also being tested in the belief that the chemical may attack the roots as well as the foliage.
So being that there is a real risk to our Heath here we need some simple guild lines
Never harvest from any public place such as on foot paths , cycle paths roadsides or parks as the local council will defiantly have some sort of preventative measures in place ,
If you feel you have found a wild patch which is not treated make a two weekly walk by for a spring summer season as if pesticides are being used visible signs will be obvious ( yes this means that harvesting in the first year is not a safe bet )
If you have Fallopia japonica on your own land or a known persons land and can be 100% sure no pesticides are used and only if 100% sure it is safe you can harvest but remember you are bound to inform the land owner of the potential problems they may face and them in turn to inform the authorities .
The other major aspect you need to take notice of is location of the growth itself as knotweed has a habit of popping up in some nasty places such as rubbish dumps and chemically infected industrial grounds it actually has been proven to actively cleanse chemically infected soil the main chemical being lead as the naturally occurring oxalic acid is able to make the lead more soluble .
You by now probably are thinking why would I go to all this trouble to bother when there are so many wild edible available which don’t require this effort to harvest well the answer is simple this invasive monster has a gift , the young shoots are something quite special they look like prime asparagus and taste like mild rhubarb and can hold its own in both sweet and savoury dishes I have used them in cakes , jams , chutney , leather and pickles and even candied the stems and never once been disappointed with my results there is also a vast argument happening as areas that are harvested for the young stems do not spread at the rate of un harvested sites it is said that a single harvest of the young shoots can effect the plant as much as a treatment with a pesticide .
My donkey jam
First I should explain I don’t use sugar in my preserves so I substitute that with honey for sweetness and I’ve got a nice bag of wild plum stones to boil up to start with to extract the naturally occurring pectin ,
But there is no reason that you can not use store purchased jam sugar
So as ingredients go it’s equal amounts of Fallopia japonica to sugar so every kg of stem needs a kg of sugar ,
One juice and rind of a lime
One kg of stem cut into equal sized cubes
One kg of sugar with pectin ( or one cup of honey per kg of stem )
Quarter cup of fresh ginger
First add the stems to one cup of boiling water and leave to simmer for five minutes then add the rind of the lime and juice and ginger root along with the sugar and allow to simmer for a further five to ten minutes until the stems are soft and translucent and the jam has reached setting point which is 105c (220F) . If you don’t have a thermometer then a simple test to determine if your jam will set can be used , put a ceramic plate in the freezer when you start your jam and when it has boiled for about three minutes take the pan off the heat and put a small spoon of jam on the plate and push it with your finger and it should ripple if it does your jam will set if not just boil for longer and repeat the test .
It is a little known fact that Fallopia japonica contains daidzin which has been proven to help with alcohol dependency .
Fallopia japonica has high levels of oxalic acid which has been proven to irritate conditions such as rheumatism, arthritis, gout, kidney stones so eating high levels of this is not recommended if you suffer from any of these problems