Knotweed

[Koolpc]

It can grow very deep apparently.

Get ur mining hat on buddy!

 

[Odds]

If you do not get rid of Japanese Knotweed and allow it to spread into the wild you are legally liable for prosecution. So after you've tried and failed to dig it out, you'll have to dig deep into your pocket, too.

 

[DiyNutJob]

It can grow very deep apparently.

Did the treatment company tell you so? How deep did they say?

The internet says the following. I was right even though I never seen a knotweed.

What kills Japanese knotweed permanently?

Physical Removal - Excavation and removal of the underground root and rhizome system, ensuring Japanese knotweed is gone, and gone for good. Herbicide Treatment - Is a control method, as while herbicide can kill immature plants, it's less effective on mature rhizomes, often causing dormancy rather than death.

 

[Koolpc]

Did the treatment company tell you so? How deep did they say?

The internet says the following. I was right even though I never seen a knotweed.

What kills Japanese knotweed permanently?

Physical Removal - Excavation and removal of the underground root and rhizome system, ensuring Japanese knotweed is gone, and gone for good. Herbicide Treatment - Is a control method, as while herbicide can kill immature plants, it's less effective on mature rhizomes, often causing dormancy rather than death.

Weedkiller control​

It usually takes at least three to four seasons to eradicate Japanese knotweed using weedkiller. Professional contractors, however, will have access to more powerful weedkiller that may reduce this period by half.

Japanese knotweed / RHS Gardening

Japanese knotweed (<em>Reynoutria japonica </em>syn. <em>Fallopia japonica</em>) is a weed that spreads rapidly. In winter the plant dies back to ground level but by early summer the bamboo-like stems emerge from rhizomes deep underground to shoot to over 2.1m (7ft), suppressing all other plant...

www.rhs.org.uk

 

[DiyNutJob]

It usually takes at least three to four seasons to eradicate Japanese knotweed using weedkiller. Professional contractors, however, will have access to more powerful weedkiller that may reduce this period by half.

What is the reason the "professional contractors" were not able to remove the weed for the previous owner?

 

[Koolpc]

What is the reason the "professional contractors" were not able to remove the weed for the previous owner?

They werent employed! Lol

 

[DiyNutJob]

They werent employed! Lol

OK, it seems people unemployed is not at risk of prosecution for a run away weed. It makes sense for unemployed people to dig the knotweed up. It gives them something to do and increase the house value.

 

[charliegolf]

If it were me, i would be looking to get the strongest weed killer on the market and smother the knotweed with it!

This is a bad approach. I've been working on it for about 5 years now, and with good success. Smothering it can cause it to go dormant at rhizome level, only to come up again. When I started, I had 'rhizome clumps' 2 feet across, with the weed standing 6-8 foot tall. They had to be dug out eventually. You need to spray spring and autumn, and be disciplined!. Now I deal with smaller amounts of very new growth. First it's a red 'thumb' poking up, then grows to 2 distinct leaves. That's the time to spray, and just leave it. When it has a 'burned' look, I pick it out individually. I put it on DPM and let it dry to nothing.

I use Roseate*, and at the concentration given not 'double' strength for a bit extra!

*It's a glysophate- like Roundup on steroids. Agricultural suppliers might have supplies.