Identifying Japanese Knotweed

Share This Post

Table of Contents

Japanese knotweed can be hard to identify in your garden because it’s often mistaken for a harmless plant or goes unnoticed by the untrained eye. However, if an infestation is left to run rampant or grows too close to a property of infrastructure, it can cause severe and costly damage, making it one of the UK’s most dangerous plants.

The best way to avoid a Japanese Knotweed infestation is to remove the plant in its early stages and have it dealt with by professionals.

How to identify Japanese Knotweed?

The most noticeable feature of Japanese knotweed is its heart-shaped or shovel-shaped leaves. Depending on the time of year, the plant’s appearance changes, making correct identification even more difficult. The shoots of Knotweed have a reddish-purple hue when they first start to grow, and light green leaves develop fairly early on.

In summer, the stems may start to resemble bamboo shoots and will develop purple specks. The leaves will grow larger and have distinctive ribs and veins. Late in the growing season, you may see small, cream-coloured flowers developing. These flowers are formed of dense clusters of small flowers on thin spikes around 10cm long

As autumn progresses, the leaves will turn yellow and slowly wilt. The stems then turn brown, and the plant enters its dormant winter stage. Throughout the Autumn to Winter transitional period, Japanese Knotweed still has the tremendous power to grow up to 3 metres.

Images of Japanese Knotweed

What other plants look like Japanese Knotweed?

Many plants are often mistaken for Japanese knotweed, including the Himalayan balsam plant, bindweed, broadleaf dock, Russian vine and some lilac shrubs.

For example, the leaves of bindweed are heart-shaped, making them look similar to Japanese knotweed. One distinguishing factor is that bindweed is a climbing plant, hence it tends to wrap itself around structures and walls in the garden.

Due to the difficulty of identifying Japanese knotweed and the benefits of early detection, it’s recommended to seek professional assistance if you suspect you have this invasive plant in the form of a survey. In most cases, a survey will be completed to determine the presence or absence of the plant over an area of land. Once the survey has been completed, you’ll receive confirmation or deny the presence of the invasive perennial plant, along with a recommended plan of action.

Where does Japanese Knotweed grow?

Japanese knotweed thrives in a diverse range of growing conditions and soil types. Its rapid growth rate makes it one of the most troublesome and invasive plants in the United Kingdom.

If allowed to spread freely and given suitable growing conditions, Japanese Knotweed can quickly invade large areas. Capable of growing up to 3m in height and spanning several metres underground from the plants visible source, the rhizome systems help to rapidly increase the rate at which Japanese Knotweed can be seen sprouting above ground.

Sites such as railway lines, derelict construction sites, and waterways are popular habitats for the plant, where the spready often left largely uncontrolled.

How do I remove Japanese Knotweed?

Due to the plant’s invasive nature, self-treatment or removal without the proper equipment is not recommended. In fact, it is illegal in the United Kingdom to spread Japanese knotweed onto other land, so attempting to remove it yourself could land you in trouble.

The few safe disposal methods available include incinerating, disposal at an approved facility, and burial beneath a protective membrane, but they are not feasible for most hobbyist gardeners. 

GET IN TOUCH

Are your pictures on a different device? Don’t have pictures available at the moment? No problem! Sending pictures to us is EASY at ANYTIME. You can contact us via the following:

SMS Text

WhatsApp

Facebook

Twitter

Instagram

Video

1 Step 1
FREE IDENTIFICATION
Fill in the form below, attach your pictures and we'll let you know if the plant in your picture is Japanese Knotweed.

Please choose from one of the following:

By sending this form I consent to let Knotweed Services (UK) Ltd collect and store the personal data contained in the above form submission, so that they can respond to my enquiry. 

keyboard_arrow_leftPrevious
Nextkeyboard_arrow_right
FormCraft - WordPress form builder

More To Explore

ARE YOU SURE ABOUT THAT? Did you know the characteristics of Japanese Knotweed significantly change when it has been treated incorrectly! Let …

Knotweed Services (UK) LTD are pleased to announce we are now an approved contractor for Dignity Caring Funeral Services. We very much …

With the long and cold winter of 2017/2018, the growing season for Japanese Knotweed has been delayed. We would normally see the …

We use cookies to give you the best online experience. We do not pass over any personal information to 3rd parties via our cookies. If you do not accept cookies, our website may not display or function correctly.

Privacy Settings saved!
Privacy Settings

When you visit any web site, it may store or retrieve information on your browser, mostly in the form of cookies. Control your personal Cookie Services here.

These cookies are necessary for the website to function and cannot be switched off in our systems.

In order to use this website we use the following technically required cookies
  • wordpress_test_cookie
  • fc_sb_1

Decline all Services
Accept all Services