Japanese knotweed study into its permanent eradication

Plants that look like Japanese Knotweed?

Japanese Knotweed is commonly misidentified by many people including architects and housing surveyors. Therefore, it is important that you are able to identify plants that look like Japanese Knotweed.

Knowing how it can uncertainty during mortgage applications with both anxious homeowners and potential buyers alike. Do not worry. Most professional Japanese Knotweed removal companies provide a free knotweed identification service.

Simply take a photo and send to them for their analysis. If it warrants more of an investigation you have the opportunity to carry out a full survey. This will be chargeable.

Most Popular Plants that look like Japanese Knotweed

There are many plants that look like Japanese knotweed and have similar characteristics. The plants that are most commonly mistaken for Japanese knotweed are:

  • Bindweed
  • Hedge Bindweed
  • Russian Vine
  • Giant Knotweed
  • Broadleaf Dock
  • Common Dogwood
  • Daphne Lilac (superba)
  • Common Elder
  • Himalayan Balsam
  • Himalayan Knotweed
  • Lesser Knotweed
  • Himalayan Honeysuckle
  • Ground Elder
  • Houttuynia Cordata
  • Bamboo

While these plants do not contain all the features of knotweed, they have enough of a similarity to cause anxiety.

Bindweed is just one of many plants mistaken for Japanese knotweed

Bindweed (Convolvulus arvensis)

How Bindweed looks similar to Japanese Knotweed
With its heart-shaped leaves, Bindweed may look similar to Japanese Knotweed. The leaves of Bindweed also alternate along the stem and, much like knotweed, when it appears in spring, Bindweed can cover a large area very quickly.

How you can tell the difference between Bindweed and Knotweed
As its name suggests, Bindweed is a climbing plant that grows by twisting around the stems of other erect standing plants; it is unable to support itself and grow straight up as Knotweed does.

You will also notice large, pink or white, trumpet flowers start to grow in early summer, which distinguishes it from Japanese Knotweed.

How to get rid of Bindweed
Since it grapples on to other plants in your garden, Bindweed can be difficult to eliminate with herbicides. If you don’t want to damage the other plants, you can apply a spot weedkiller to the leaves which will be absorbed. Also, by cutting the plant down to ground level, it will have to use up its energy reserves in its roots, which will eventually kill it.


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Broad-leaved Dock (Rumex obtusifolius)

How Broad-leaved dock looks similar to Japanese Knotweed
Part of the same family, so hardly surprising that it looks similar to knotweed, Broadleaved Dock has leaves arranged alternately along the stem as well. Its flowers and stems also form spikes just like knotweed.

How you can tell the difference
Stems are fluted and shorter than knotweed plants, growing up to 1m in height. The stems are not completely hollow and contain a foam-like substance when snapped open.

How to get rid of Broad-leaved Dock
Roundup herbicide should do the trick if you don’t mind using herbicides in your garden, otherwise, you could try boiling water or vinegar. If you decide to dig it up, you’re going to need to go down three feet to get every last trace of root out and avoid a regrowth.


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Rumex Crispus - Broadleaf Dock
Bamboo stems similar to Japanese Knotweed

Bamboo

How Bamboo looks similar to Japanese Knotweed
Clear nodes on it stems and the fact that it can easily grow as tall as knotweed, if not higher, means the two are easily confused.

How you can tell the difference between Bamboo and Knotweed
Take a look at the leaves, those of bamboo are much longer and thinner, also the stem is much harder, you won’t be able to snap it with your fingers very easily.

How to get rid of Bamboo
Bamboo roots grow very close to the surface, so smaller infestations can probably be pulled up by hand, just make sure to get all the rhizomes to avoid a regrowth. For larger infestations, cut the stems close to the ground and pour Roundup herbicide down the hollow shoots. You can keep bamboo contained in your garden by using root barriers.


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Himalayan Balsam (Impatiens Glandulifera)

How Himalayan Balsam looks similar to Japanese Knotweed
Just like Japanese Knotweed, Himalayan Balsam is a fast grower; it can quickly cover a large area and grow as tall as 2.5 metres. And like Japanese Knotweed, it also has a hollow stem.

How you can tell the difference between Balsam and Knotweed
Take a look at the stem and you will see the leaves grow opposite each other rather than in an alternating pattern like Japanese Knotweed does. The leaves themselves are also much longer and thinner too, with a pink midrib.

Watch out for the large, pink, hooded and lipped flowers which will form in mid to late summer.

How to get rid of Himalayan Balsam
Unlike Japanese Knotweed, Himalayan Balsam propagates via seeds, which will explode upon touch when ready. Cutting the plants down to ground level can stall their progress, but by sure to plan your attack for the end of June; too late and you risk spreading the seeds, too early and you risk precipitating a regrowth of new stems.


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The serrated, pointy leaves of the Himalayan balsam
Himalayan knotweed leaves - long and tapered

Himalayan Knotweed (Persicaria wallichii)

How Himalayan looks similar to Japanese Knotweed
With a very similar stem to Japanese Knotweed, it can easily be mistaken when not in bloom. You’ll also find that it has a hollow stem-like knotweed and that the leaves are alternately arranged along the stem too.

How you can tell the difference between Himalayan and Japanese Knotweed
You can easily tell the difference by the leaves, which on the Himalayan Knotweed are very narrow, often half as wide as they are long. On closer inspection, you’ll also note that the stem is much thinner, growing to around 1cm in diameter.

The flowers on Himalayan Knotweed have a pink hue, which distinguishes them from the pure white of Japanese Knotweed’s.

How to get rid of Himalayan Knotweed
Himalayan Knotweed originated in Western Asia, but it is just as pernicious as its Japanese cousin, and you should call Japanese Knotweed Specialists as soon as you have identified it to arrange a herbicidal or excavation removal process.


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Himalayan Honeysuckle (Leycesteria formosa)

How Himalayan Honeysuckle looks similar to Japanese Knotweed
Himalayan Honeysuckle has hollow stems which can look a lot like knotweed and can also be broken fairly easily.

How you can tell the difference
The leaves growing opposite each other along the stem distinguishes it from knotweed, as do the pale green stems with no purple speckles. It becomes easier to identify in late summer when its distinct drooping white flowers sprout from pendulous racemes.

What to do about Himalayan Honeysuckle
Cutting it right down to the ground and painting over the stump should do the trick, or you could also apply a herbicide. To prevent a regrowth, be sure to replant with other plants.


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Close-up image of Himalayan honeysuckle flowers and foliage
Russian vine white flowers growing in clusters

Russian Vine (Fallopia baldschuanica)

How Russian Vine looks similar to Japanese Knotweed
Also a fast-growing plant, Russian Vine sprouts leaves and flowers which can appear very similar to Japanese Knotweed.

How you can tell the difference between Russian Vine and Japanese Knotweed
Unlike Japanese Knotweed, Russian Vine is a climbing plant and relies on the erect stems of other plants or solid structures to twist around and grow up.

How to get rid of Russian Vine
Locate the trunk, saw through it and paint poison on the stump which will then be absorbed. You can also use herbicide by stuffing as much of the plant as you can into a plastic bag and spraying liberally with glyphosate, then tie up the neck of the bag securely and leave.


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Lilac and woody shrubs etc…

How it looks similar to Japanese Knotweed
The leaf shape of many woody shrubs like lilac can look similar to Japanese Knotweed.

How can you tell the difference?
The stems of Japanese Knotweed are not wood at all, so you can rule out anything with bark or twigs that show solid wood when snapped


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Japanese knotweed leaves
Japanese Knotweed in late summer and in full bloom

What does Japanese Knotweed look like?

If you want a clearer idea of what Japanese Knotweed looks like click the button below.


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What to do if you are still unsure?

If you are you unsure if you have Japanese Knotweed or something else growing on your land then you can contact a local Japanese knotweed specialist who will help you identify what you have on your land. Most specialists these days offer a free photo identification service to clarify what you have and whether it needs investigating more.

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