Japanese knotweed is relatively easy to identify, once you know what the characteristics are. These include;
• Asparagus-like spears emerging in spring • Bright green shield shaped leaves that form a zig-zag shape on the stem • Tall green canes, with purple speckles • Clusters of creamy white flowers in late summer • Brown, brittle canes left standing in winter
Take a look at the images below. You can also visit our picture gallery and watch our 3 minute video on How to identify Japanese knotweed. We've also produced a Japanese knotweed Identification Guide, which you can download to help you identify the plant in situ.
Not looking quite right? Check our Japanese knotweed Hybrids and Commonly mistaken plants galleries to be sure.
If you are still unsure, we offer a Japanese knotweed identification service. Email your photos to firstname.lastname@example.org and we'll tell you if Japanese knotweed is present.
This is a free service. However, if you would like to make a small donation to a worthy charity via JustGiving that would be appreciated.
About Japanese knotweed
Japanese knotweed (Falopia Japonica syn. Polygonum cuspidatum) is a highly invasive non-native weed that can damage foundations and driveways, as well as putting a stop to mortgage applications and construction development plans.
First introduced to the UK from Japan in the 1840s as an ornamental plant, Japanese knotweed is now widespread throughout the UK and can be found as a wayside weed and in many private properties across the country. To find out more about the origins of the plant, read our page on Japanese knotweed history, or get yourself to a copy of MD Nic Seal's book Unearthing the Truth.
Mortgage lenders require a Japanese knotweed management plan with an insurance backed guarantee to be in place before they will lend on properties with this prolific perennial. Knotweed has the ability to cause significant damage to tarmac, concrete, paving slabs and foundations of properties.
There are also various legal considerations when dealing with Japanese knotweed. Private nuisance claims can be brought against a landowner who allows knotweed to spread into adjoining land. Under the provisions made within the Wildlife and Countryside Act 1981, it is an offence to cause Japanese knotweed to grow in the wild.