Japanese Knotweed Control - Death by Lethal Injection

A plant-eating predator from Japan could be used to control a superweed spreading throughout the UK, scientists believe, reports the BBC web site today.

Japanese Knotweed is an evasive weed that must be controlled now. Its' spread across the United Kingdom has been assisted greatly by lack of education and the dumping of garden green waste at waste transfer stations and local amenity dumps.

Our knowledge base is of course lawns and their care but we thought that you would be keen to be kept informed on other weed related matters.

The Environment Agency have drawn up advice on the control of the weed which is listed as a weed that must be controlled under the Wildlife and Countryside Act 1981.

The article which appeared today on the BBC News web site reports that a new biological control is being developed to naturally control the weed.

Listening earlier today to the BBC Radio 2 - Jeremy Vine Show, Jeremy invited home owners to call into the show to discuss their experiences with the weed on their properties. Responses varied from those who dug it out, to chemical control and attacking it with a flame gun at regular intervals. What Vine failed to give out on the radio show was some practical tips for the home owner to assist in the eradication of the weed without the need to call in Professional Chemical Treatment Contractors.

Education and correct diagnosis is paramount to stop it going to the dump and being recycled into green waste compost. Digging it out is not an option as the weed has very strong underground rhizomes where just a small piece left in the soil can regenerate quickly.

Here is our advice in the eradication of small iinfestations of the weed in domestic/home owner situations. We are BASIS Registered so able to give out advice relating to the use of Pesticides.

The best method of control is via chemical control. Chemical control can take place as a blanket spray over the canopy of the clumps but not ideal if the clumps are over knee height. Damage may also occur to desirable plants that you want to retain. One tried and tested solution is to inject with a syringe around 10 ml of neat chemical into each individual plant stem at aroung waist height. Injecting it at this height makes the operation a little safer. You could mark each injected stem with a small piece of masking tape once completed so identification of treated Vs untreated stems is made easier. The chemical to be injected is based upon Glyphosate and one with at least a 360 grams per litre strength. It is available from Garden Centres and DIY Outlets or from The Lawn Shop. Roundup Ultra 3000 is an economical, concentrated liquid for use in watering cans and sprayers. Kills weeds and roots. This systemic weedkiller goes in through foliage and moves right down to the root tips to kill off the whole plant. Ideal for large areas and tough weeds. Leaves no harmful residues - allows replanting. Children and pets need not be excluded from treated areas. One Litre will therefore be sufficient to treat up to 100 stems.

Be very careful NOT TO SPEAR YOURSELF WITH THE SYRINGE NEEDLE whilst in the process of using it. You could use a small piece of wood just behind the stem to ensure hands are kept clear during the insertion of the syringe. Leave for around four weeks for the product to work in the growing season and then re treat any new growth once it is about one foot tall. Do not disturb the soil during the programme of control and burn any old dead stems. Dispose of all used syringes carefully!

Let us have your comments and experiences of this obnoxious weed.

Comments

[Mike Seaton]

Cathy

The Japanese Knotweed will not survive regular mowing so it should not develop. Hope this helps. Mike

[cathy jones]

What do I do if the knotweed is growing up through my lawn?? We thought we had eradicted all the knotweed on our site two years ago before we relandscaped. Last year we had two plants growing up in one bed and were abe to let them grow and then inject them. This spring I have seedlings growing up all over the lawn and don't know how to deal with it as letting it grow tall enough to inject obviously means no lawn....Any ideas anyone???

[Mike Seaton]

Thanks Ian for this, input appreciated. Mike

[Ian Benison]

You may be interested in our nationally accredited training course on Awareness of Japanese Knotweed and control of non native plant species, the web site is http://www.slictraining.org.uk