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What does Japanese Knotweed look like in winter? | JBB Knotweed Solutions

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What does Japanese Knotweed look like in winter? A Seasonal Guide

As the colder months settle in, it’s crucial for homeowners and garden enthusiasts to understand how Japanese Knotweed behaves during this time of year. Japanese Knotweed (Fallopia japonica) is a highly invasive plant species known for its relentless growth. While it may appear dormant in winter, it still poses challenges. In this guide, we’ll explore how to identify Japanese Knotweed, whether it grows during this season, and what changes it undergoes in the cold months.

What does Japanese Knotweed look like in Winter? Life cycle image of Japanese Knotweed by Removal Specialists JBB Knotweed Solutions

How to Identify Japanese Knotweed in Winter

Identifying Japanese Knotweed during winter requires a keen eye. While the plant’s lush green leaves have withered away, leaving bare stems and empty space, several key characteristics can help you spot it:

Dark-Brown, Hollow Bamboo-Like Canes

Japanese Knotweed stems are thick, woody and hollow, resembling bamboo. These stems can reach impressive heights, even in winter, and are usually dark reddish-brown and bare.

Dead Brown Leaves, Flowers and Stems

While the plant loses its heart shaped leaves in winter, you may still find dead, papery leaves attached to the stems, giving a distinctive appearance. The remanence of the dead flowers will remain for a time, forming spider-like curled, dead growth. The alternate stem arrangement will remain evident until it falls off and decomposes.

Later in winter, all that may remain are the dead, hollow bamboo-like canes that may be seen in the ground and still connected to the crown and root system.

Reddish Purple Shoots

Keep an eye out for new shoots emerging from the ground. Even in winter, Japanese Knotweed can produce small reddish or purple shoots that hint at its presence. Early shoots may appear, like small red arrows, towards the end of winter.

Rhizome System

Japanese Knotweed’s extensive underground rhizome system remains active beneath the surface, ready to fuel its growth once spring arrives.

Does Japanese Knotweed Grow in Winter?

Japanese Knotweed is classified as a perennial plant, which means it doesn’t die off entirely in winter. While its above-ground growth appears dormant, the plant’s underground rhizome system remains active. This system allows Japanese Knotweed to store energy and nutrients for the coming seasons.

During winter, Japanese Knotweed conserves its resources, waiting for the right conditions to re-emerge vigorously in spring.

So, while it may not actively grow during the coldest months, it is far from defeated. Proper management is crucial to prevent it from spreading further – learn more by reading our Frequently Asked Questions.

What Happens to Japanese Knotweed in the Winter?

Winter serves as a respite for Japanese Knotweed, allowing it to prepare for the upcoming growing season. Here’s what happens to this invasive plant during the winter:


Above-ground growth, including leaves and stems, dies back. The plant enters a state of dormancy to conserve energy.

Rhizome Storage

The extensive rhizome system beneath the soil stores energy and nutrients. These underground reserves are essential for the plant’s rapid growth in the spring.


Japanese Knotweed’s ability to survive harsh winter conditions, combined with its rapid growth potential, makes it a resilient and persistent threat.

What to do if you discover Japanese Knotweed during winter

The most important thing to do if you discover or suspect that you have Japanese Knotweed on your property during is simply not to disturb it or think that it is safe to try and ‘dig out’. It is also best to leave the dead stems and nodes of the plant to die back and fall off naturally, in order to prevent inadvertently removing and spreading propagules.

Rapid action is always best when dealing with Non-Native Invasive Species (INNS) and contacting a Japanese Knotweed specialist like JBB Knotweed Solutions at the earliest opportunity should be a priority.

Can you remove Japanese Knotweed during winter?

Japanese Knotweed can be removed by specialist excavation during winter and the lack of other foliage and growth can even make mechanical excavation of the plant easier. This enables us to track and remove root system material for off-site disposal to a licensed landfill site or remove it for management elsewhere on site. This is often preferable when development works are planned or timings won’t allow a longer-term treatment method such as herbicide application.

If you suspect that you have Japanese Knotweed on your property, book a survey for friendly advice and support.

Book a Japanese Knotweed Survey

We can tell you if you definitely have Japanese

Knotweed on your property and recommend the

best course of action.

We can tell you if you definitely have Japanese Knotweed on your property and recommend the best course of action.