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Gardening

Japanese knotweed

(18 Posts)
NonnaW Tue 28-Aug-18 08:40:02

DH has discovered something in the garden that he fears may be Japanese Knotweed. Can anyone say if this is it?

NonnaW Tue 28-Aug-18 08:40:44

Sorry not the best of photos

Iam64 Tue 28-Aug-18 08:44:49

You will probably find lots of images if you consult Garden Google. I read recently, if its found, its no longer seen as an issue that affects any potential house sale. I'd murder it and keep on the assault. Good luck.

tanith Tue 28-Aug-18 08:48:38

Take a picture of the shoots that would be easier to identify.

NonnaW Tue 28-Aug-18 09:03:14

Thanks tanith. It is exactly the fear of it jeopardising the house sale that has kicked this off. DH only noticed the plant recently and sprayed it with weedkiller but on completing forms yesterday when we stated we had none, he had a sudden panic. I personally don’t think it is, comparing it to a google photo, but I think we might have to get someone in jot check, just to put our minds at rest.

NonnaW Tue 28-Aug-18 09:03:50

Just to, not jot.

merlotgran Tue 28-Aug-18 09:09:57

Have you ever seen it in flower?

Greyduster Tue 28-Aug-18 09:21:32

The leaves don’t look the right shape for knotweed. Are the stems hollow?

J52 Tue 28-Aug-18 10:03:33

From the photo the stems look woody and the leaves rather leathery for JK. But that could be due to the weed killer.
BTW just spraying with weed killer has little effect. The ‘experts’ suggest cutting it back ( burning the cuttings) to a stalk and pouring the weed killer down the hollow stem.
Not that I’ve done it myself.
I hope it isn’t JK.

Jalima1108 Tue 28-Aug-18 10:09:02

Himalayan Balsam is also a very invasive species but tends to grow along river banks.

The stems do look rather woody - did it flower? If so, do you have any photos of the flower?

Could it be a mallow shrub? Just a possibility, as the leaves may the wrong shape but that has woody stems and pink flowers. It is a garden shrub.

However, it is best to make sure.

Blinko Tue 28-Aug-18 10:21:16

With Knotweed, the stems are hollow. They should be cut off at about two feet from the ground and Glysophate poured down them. This will eventually destroy the rhizome which runs beneath the ground. Spraying with weedkiller won't get rid. In the years following, you should keep watch and apply the treatment again, till it doesn't reappear. Persistent bugger, Knotweed.

NonnaW Tue 28-Aug-18 11:14:23

We only sprayed it with weedkiller because we assumed it to be a common or garden weed. We are fairly sure we would have noticed it flowering as it is next to the apple tree and we’ve been keeping a close eye on that. Next step then is to cut a stem to see if it’s hollow.

Thanks for all the input ladies.

pembers66 Thu 30-Aug-18 14:44:59

This isn't knotweed (I work for a professional knotweed remediation company).
I've attached some images of knotweed so you can see the difference smile.

Jalima1108 Thu 30-Aug-18 15:41:16

Thanks pembers66, very useful.

Can I ask a question:
Sometimes we see a lot of foliage climbing and draped all over the trees when we are travelling in the countryside near our family. At the moment it is smothered in white flowers.
Does knotweed flower? If so, would you happen to have a picture you could post?

We see a lot of what we think is Himalayan Balsam too; that has pink flowers.

Thanks

MaizieD Thu 30-Aug-18 16:27:28

If it's climbing high into the trees and has like pannicles of little white flowers it could well be Russian Vine (or. mile-a-minute), Jalima. I've seen it climb to the top of a 30 foot tree and still look for pastures new grin

www.sundaygardener.co.uk/fallopia_also_known_as_mile_a_minute_plant.html

Another thug which is hard to get rid of, but not as vile as Japanese Knotweed.

What does your firm recommend for Knotweed, then, pembers66? We were told by a professional gardener never to cut it down as the tiniest bit will root easily. We've a patch in the old garden I volunteer in. Over 4 years it's had bonfires on top of it, deisel down the stems, regular attacks with a flame thrower and superstrength weedkiller. It's very resistant! But apparently the young shoots are edible..

Jalima1108 Thu 30-Aug-18 16:36:38

Ah, MaizieD that could be it. It's just that it is all over a tree near a friend's house too, so I will have to have a sneaky look at the leaves.
Thanks.

knotweed18 Tue 16-Oct-18 16:56:39

This is still pembers66 - I forgot my login details, so I've had to set up another account!

I agree with MaizieD - Russian Vine looks very similar to Japanese knotweed. The flowers are so similar.

The difference is that Japanese knotweed grows in canes - like bamboo.
Russian vine creeps and binds around other plants and structures.
For knotweed, we don't recommend cutting it or disturbing it. You're right, the smallest bit (as little as 0.7g) can give rise to a brand new plant.
A herbicide treatment programme is the best option. Glyphosate is the chemical of choice. Spray onto the leaves (wait until a good amount of foliage is present - you need the surface area) in the spring and then in the autumn. You will need to repeat for at least 3 years.
Here is more information on herbicide treatment. If you browse through the site, you'll also find useful information on identification and what I call "look-a-likey" plants (plants that look like Japanese knotweed):
www.japaneseknotweed.co.uk/japanese-knotweed-treatments/chemical-treatments

paddyann Tue 16-Oct-18 18:34:49

its a problem here with selling houses,my MIL looked at a lovely flat close that she wanted to buy.When the home report came back it said there would be problems if she ever came to resell it and the buyer wanted a mortgage .The knotweed wasn't even in the grounds of the flat but in the garden of a care home across the road.That was just recently so she has decided not to move .