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Forum topic by chrisstef posted 05-01-2015 02:20 PM 1646 views 0 times favorited 67 replies Add to Favorites Watch
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chrisstef

15677 posts in 2474 days


05-01-2015 02:20 PM

Topic tags/keywords: knotweed bastard plant eradicate

Has anyone waged war against this invasive species? Ive got a good stand of the stuff just behind a fence in a wooded portion of my backyard and its beginning to creep its way into my lawn area. Needless to say, I aint havin it! Has anyone had any success in eradicating this SOB?

From what ive read the only type of warfare its susceptible to is chemical. 2,4-D and other herbicides that contain glyphosate such as concentrated roundup are supposed to be the ticket but will likely need to be applied directly to a freshly cut stem / shoot of the plant.

I hates me some knotweed.

-- rock, chalk, jayhawk


67 replies so far

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SirIrb

1239 posts in 698 days


#1 posted 05-01-2015 02:22 PM

BURNED MOTOR OIL.

[sound of weeds screaming]

-- Don't blame me, I voted for no one.

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chrisstef

15677 posts in 2474 days


#2 posted 05-01-2015 02:23 PM

Sounds of my Department of Environmental Protection employed wife screaming ^

But I guess at some point ill resort to just about anything lol. She’s gotta go to sleep some time.

-- rock, chalk, jayhawk

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SirIrb

1239 posts in 698 days


#3 posted 05-01-2015 03:34 PM

It is the best weed killer. Back home in South Mississippi kudzu can not be stopped short of mowing it and never letting the leaves get sun, rinse, repeat for years. But the mower wont get in fence rows. oil will.

-- Don't blame me, I voted for no one.

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7Footer

2543 posts in 1416 days


#4 posted 05-01-2015 03:49 PM

Hey buddy, asked my old man about it, it’s pretty bad here in Oregon too, especially in the coastal areas. Sounds like the timing of when you spray is the key, as which is the same with most invasive species. Basically you need to spray it in the fall if you want to stop the rhizomes from spreading, if you spray it now it will help, but it won’t stop it… Sounds like that is some nasty ish, and you got some work cut out for you.

If you need some herbicides, I can most likely hook you up, we’re a licensed chemical dealer, that round up pro sh!t is expensive, and it’s all a name, glyphosate is cheap and I bet we have some lying around. Just look at what percent of active ingredient is in pro vs. pro concentrate… My pops was saying that with round pro concentrate, it has a little extra ingredient in it which turns the leaves and foliage brown quicker than a straight glyphosate, but that doesn’t really mean it’s gonna kill the plant or the rhizomes, and the active ingredient between pro and pro concentrate is not a huge amount.. It said fall is the most effective time to spray knotweed because that’s when the roots are absorbing more nutrients and thus will absorb more of the herbicide into its roots…. I guess that the root systems of knotweeds are so massive that’s part of what makes it very hard to control.

There’s a couple people I can ask and see if anything in particular works better than other products, they’re noxious weed ‘sperts.. I found this article about it though, sounds like you’re pretty much right on though, glyphosate.
http://extension.oregonstate.edu/gardening/node/965
Here’s some more good links
http://extension.oregonstate.edu/search/google?cx=003321618576478813351%3Aw55shzhvmvg&cof=FORID%3A11&query=knotweed&sa.x=0&sa.y=0&sa=Search&form_build_id=form-jife48W-72yHUiTQiJUs5VqYSQ-Edi3z86OkED55_04&form_id=google_cse_searchbox_form

-- http://www.youtube.com/nrk411

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AnthonyReed

8743 posts in 1908 days


#5 posted 05-01-2015 03:50 PM

EDIT: Never mind, I deffer to ^. This is 7’s wheelhouse, he’ll set you straight.

If you are diligent with a systemic herbicide like roudup wouldn’t it eventually kill the root system and negate the infiltration? It reads like it is a very robust plant and will require many applications to kill the root system, which is the only way to stop it permanently. Short of that, rent a dozer and push the ish out.

I have no experience with it however Stef, I am just blathering my thoughts.

-- ~Tony

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chrisstef

15677 posts in 2474 days


#6 posted 05-01-2015 03:55 PM

I forget what you do for a living sometimes 7 … doh! Definitely talk to you people and see what you can dig up for a brother. Ive sent an email over the invasive species department at UConn to see what they might be able to offer as well.

From what ive read 41% glyphosate seems to be the standard in roundup concentrate and other similar products. Gimme dat good ish if you got it buddy! I think I can get 46% stuff at the depot but im always on the look out for the real deal goods.

If ive got to cut the shoots one by one and inject them with death juice I will. Little motor oil for you, lil gylhosate for you, little magic dust for santy claus.

-- rock, chalk, jayhawk

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woodcox

1576 posts in 1479 days


#7 posted 05-01-2015 04:00 PM

Here ya go. Give 7’rrr a call to see if he has a couple loaners that are “out of rotation”.

Out of control that stuff looks like it could hide a house! Good luck with that mang.

-- "My god has more wood than your god" ... G. Carlin.

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chrisstef

15677 posts in 2474 days


#8 posted 05-01-2015 04:08 PM

I think youre dead on T. Its gonna take time and effort which im willing to do. From what I read, even if you pull this stuff by the roots, one little spec of root will cause regermination.

-- rock, chalk, jayhawk

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ChrisK

1809 posts in 2549 days


#9 posted 05-01-2015 04:22 PM

An article i read suggested covering it tarps to block all the sunlight. Takes time but appears to work.

-- Chris K

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7Footer

2543 posts in 1416 days


#10 posted 05-01-2015 04:25 PM

Yeah I’m sure motor oil will work, lol. Just don’t let anyone see you doing it!

I’ll let you know if I hear anything from the foresters we work with. Sh!t sounds bad though, the root systems of that knotweed are like 10x the size of their foliage (compared to most trees that are 1 to 1 root system vs foliage), which is why it spreads so much…

Edit: ha WC!

-- http://www.youtube.com/nrk411

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terryR

6324 posts in 1776 days


#11 posted 05-01-2015 05:10 PM

+1 to the goats.
Stef, I know where you can buy a couple of kids!
:)

-- tr ...see one, do one, teach one...

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chrisstef

15677 posts in 2474 days


#12 posted 05-01-2015 05:14 PM

Ive heard that as well Chris. Ill actually be pulling out around 500 sqft of carpet from the house soon and im kind of debating on cutting the stuff back and laying the carpet over it. The only downfall is eventually ill have to throw that carpeting away and by then it’ll be wicked heavy and stink something awful im sure.

No goats Terry lol. The rest of suburbia might lose their minds if the new neighbor lets his goats run free.

-- rock, chalk, jayhawk

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chrisstef

15677 posts in 2474 days


#13 posted 05-01-2015 05:22 PM

Here’s the response email I got from the folks up at UConn:

Hi Chris,

I am glad to hear of your interest in controlling Japanese knotweed (Polygonum cuspidatum). For fact sheets and more information on this plant please visit our website and look for Polygonum cuspidatum listed on the Invasive Plant List: http://cipwg.uconn.edu/invasive_plant_list/.

This is an extremely difficult invasive plant to control due to its ability to re-grow from ½ inch vegetative pieces and from seeds. Roots and runners must be removed to prevent re-sprouting. Digging up plants is labor intensive and not recommended since digging tends to spread rhizome fragments which generate new shoots. Here are my recommendations:

Cut plants several times during growing season:
Cutting repeatedly stresses the plants and greatly reduces the reserves in below-ground rhizomes. At least three cuts are needed in one growing season to offset rhizome production. Cutting can be done at any time during the growing season but must be done repeatedly. Repeated cuttings should be continued for several consecutive years.

Shading, in conjunction with cutting, will help to weaken plants because Japanese knotweed requires high light intensities.

• I have heard varying degrees of success with shading but this is an option: After cutting, stands can be covered with black plastic or shade cloth topped with asphalt, blocks, or stones. Plastic should be kept level with the ground and coverage should extend at least 10 feet beyond the farthest stems. Weigh down the edges and monitor for sprouts. Leave cover in place for at least two growing seasons.

Cut and spray plants in the fall:
Chemical control is most effective in the fall (before first killing frost) when plants are translocating nutrients to the rhizomes. Cut stalks about 2 inches above ground level and immediately apply glyphosate (Roundup) or triclopyr (Garlon) to the cut stems. A follow-up treatment may be needed to control re-sprouts. *Always follow all directions on the herbicide label

Disposal:
These plants should not be composted at all because they have rhizomes that may survive in compost and spread to new locations when the compost is distributed. Do not bring to a transfer station, compost site, or brush processing site that may compost or mulch the material. Plant material can be bagged (tied in heavy duty black plastic bags) and allowed to rot in a sunny location for several weeks, then disposed of in trash to be placed in land fill or incinerated. Where burning ordinances permit, plant refuse can be dried out thoroughly above ground and burned on site. Plant parts should not be allowed to contact soil during this time to prevent sprouting. Incineration of material may be a viable option if it can be transported securely to an incinerator. Contact your town to find out if your regular solid waste/trash is incinerated. A guide on proper disposal can be found on our website at: http://cipwg.uconn.edu/wp-content/uploads/sites/244/2014/01/InvasivePlantDisposal_2014-01-23.pdf

Japanese knotweed will not be controlled easily. It takes diligence throughout many growing seasons and even then will require constant monitoring for seedlings and re-sprouts.

I hope this information is helpful in understanding the challenges and techniques for controlling Japanese knotweed and I wish you success in the battle ahead. Please let me know if you have any additional questions or concerns.

-- rock, chalk, jayhawk

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7Footer

2543 posts in 1416 days


#14 posted 05-01-2015 05:23 PM

Stef-san, you’re in luck. Talked to one of our good customers who is the Chief Forester for a timberland management company in Corvallis… Super knowledgeable guy. He said it’s all about Imazapyr, anyone who says glyphosate is the key is behind the times. lol. Two products that work on it that contain Imazapyr are Polaris AC and Habitat, and I know we have something sitting around, probably some Polaris. He also said you have to wait until after the 4th of july to spray it because that’s when the carbohydrates start going back into the root systems, and that’s when you can kill it. He said that he’d be happy to coach you through it if you want to give him a call. He is an awesome guy, really fun to talk to… He also breeds prized pigs, ha!

-- http://www.youtube.com/nrk411

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AnthonyReed

8743 posts in 1908 days


#15 posted 05-01-2015 05:27 PM

^Good man.

-- ~Tony

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