Japanese Knotweed

The very mention of Japanese Knotweed will strike fear into the hearts of anyone who has been unfortunate enough to encounter this destructive plant.

For those home owners or home buyers who have yet to experience this relatively recent phenomenon firstly thank your lucky stars and secondly read on!!!!

Why should we all be aware of Japanese Knotweed?

The plant is an invasive plant that can cause damage to footpaths, driveways, patios and in the worst case scenario it can get into the home itself and cause damage to foundations and drainage systems.

Why not just dig it up then?

Once established, the eradication of Japanese Knotweed can be a very costly and time-consuming exercise. The Royal Horticultural Society states on its website ‘Eradication requires steely determination’.

There are many ways of eradicating the problem including excavation, biological control and chemical control – Costs just for remedial works will often run into the thousands of pounds and that does NOT include the cost of making good any damage.


Historically, Japanese Knotweed has normally been associated with overgrown, sites usually adjacent to rivers/streams, railway lines and other areas where regular maintenance is not carried out. Consequently, properties adjacent or close to such sites are at increased risk of being affected by this plant.

However, in recent years, Japanese Knotweed has started to appear in more ‘urban areas’ – I identified Japanese Knotweed growing in the forecourt of a 1900’s mid terraced house! The property was on a street of approximately 100 similar terraced houses, surrounded on all sides by similar terraced streets extending to approximately ¼ mile. – There was NO River/Stream/Railway line or similar within half a mile of this house.

The plant itself is actually quite ‘pretty’ – In the summer it has Red speckled ‘bamboo’ style stems with green heart shaped leaves ( See Photo ), in the winter it dies back to just its stems and can be hard to spot.

The purpose of this blog is to merely highlight the problem that is ‘Japanese Knotweed’.

However if you are a homeowner and really want to be concerned (or simply want to impress someone down your local with your knowledge) can I suggest you ‘Google’ the words ‘Japanese Knotweed’ and read on in fear !!!

Blog Provided by Philip Gilbert (MRICS)

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