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How Long Can Japanese Knotweed Stay Dormant?

As winter approaches, Japanese knotweed (Fallopia japonica) enters the dormant phase of its annual growth cycle. During this period, the clusters of cream-coloured flowers will disappear and the bamboo-like canes will die away, but don't be fooled - the plant itself lives on beneath the soil.

If you've done your research, you may be aware that Japanese knotweed rhizomes can stay in the ground for a long time, dormant but not dead. This can lead to some real headaches when attempting to buy or sell a property that was affected by knotweed in the past; the plant may no longer be visible above ground, but it's difficult to know for sure that it will never reappear.


winter garden

 If you read our blog "When is the Best Time to Treat Japanese Knotweed?" you'll know that the plant prepares to die back in the autumn months by moving all its nutrients down into its rhizomes. Introducing the herbicide at this critical point in the weed's lifecycle will help ensure it doesn't re-emerge again in Spring.

But what does Japanese knotweed look like in winter? Well, like most plants, when the temperature in your garden plummets, they die back for the winter. Plants with rhizome systems like Japanese knotweed will preserve their energy and survive under the soil until more favourable conditions return. 

As for the plant you see above the surface, it becomes dry, brittle and brown. The stalks which were once red and purple and full of leaves have turned woody and bamboo-like. The canes are hollow and will collapse around each other as they die. If the area hasn't been treated until this point, you can't guarantee that the knotweed won't come back stronger in a few months time. That's why swift Japanese knotweed treatment is always recommended.

More on Japanese Knotweed Identification >

What should I do if I suspect I have a knotweed problem?

Whether you spot Japanese knotweed on your property is spring, summer or winter, it's vital that you get in touch with a professional removal company right away. You CANNOT rely on the winter months to take care of the knotweed problem for you. 

We can survey your garden free of charge to find out if the plant you've spotted is actually Japanese knotweed. If it is, we'll be able to offer you a quotation for thorough removal, meaning the knotweed won't have a chance to spread around your property further. 

Request a FREE Japanese Knotweed Survey >

If you have any questions about identifying Japanese knotweed, or if you'd like to speak to our team about treatment. Email us at or call us on 029 2039 7554.


Japanese knotweed may appear to die during the cold winter months, but it's probably still alive and lying dormant beneath the soil.

Tree in winter

As the calendar cascades from shimmering summer to auburn autumn and beyond, the weather naturally starts to get colder.

In fact, as soon as the clocks go back, it's not unusual for the temperature to drop faster than a microphone at a rap battle.

While the frosty cold and bitter chill can be a stark reminder that summertime has indeed been consigned to history, it does have its perks - particularly when it comes to garden weeds.

Most garden weeds will die out during the wintertime and spend the cold months either biting the dust or kicking the bucket - either way, few tears will be shed in remembrance.

But does Japanese knotweed die off in winter as well? Let's find out...


To Have and Have Knot

Anyone unlucky enough to have fallen foul of Japanese knotweed in the first place has likely been left frustrated to the point of nausea by the relentless persistence of the wicked weed.

However, the summertime supremacy of this invasive species does recede during the winter, losing its leafy greens and taking on a far less intimidating brittle brown appearance.

While this may seem to be a welcome reprieve for gardeners, don't let this faux farewell fool you.

Battle-tested knotweed veterans will know that this is all a clever ruse, perpetrated by the pesky plant to lull you into a false sense of security.


What Lies Beneath

Though Japanese knotweed may appear to die in winter, appearances can be deceiving.

While the colour may change and the canes may recede, a death this certainly is not. Sadly, the wintertime is merely a power-nap for Japanese knotweed, and sooner or later, the plant will rear its ugly head once more.

Such a miraculous resurrection might seem almost unfathomable, but this is no miracle. Despite the frail shoots, the knotweed rhizomes remain healthy and virtually unscathed beneath the soil and merely lay dormant in the ground throughout the winter period.

As winter turns to spring, your Japanese knotweed will rise once more like a phoenix of frustration from the ashes, ready to unleash its wrath on your garden once more.


Treating Japanese Knotweed in Winter

If you have Japanese knotweed present in your garden, why not give yourself an early Christmas present and serve your unwanted guest a festive eviction notice?

At Taylor Total Weed Control, our weed-whacking warriors are armed to the teeth with an itchy trigger finger to match - they're ready, willing and able to blow your knotty no-goodnik to smithereens.

With over 15 years of experience in the weed removal game, we have the power to banish the vexatious vine from whence it came. All you have to do is ask!

Request a FREE Japanese knotweed survey

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