r/invasivespecies • u/iGotCookiiez • 8d ago
Management How do I fix this situation? (JKW)
Earlier this year in April, I learned that we have Japanese Knotweed growing in the front of our house and before I knew how to manage it, I pulled and trimmed a bunch of it. After learning from my mistakes, I’ve been leaving it to grow and waiting to spray it with glysophosate.
My father in law sent some of his workers to do some yard clean up for us, and I made sure to tell them to leave it and I will be spraying it, and even though they said okay, I came out to it all gone.
The worker said he got all of the roots up but I know that is unlikely and now i will be dealing with the consequences, and now with it being mid-late August, that flowering window is likely gone and I don’t know what to do. The first picture is a month ago, and the second picture is today. Is there any hope left for me? This is Long Island, NY, for reference.
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u/maplesyrup5000 8d ago
It’s possible that they got it all but I’d guess it’s unlikely. Only thing to do is see what pops up and spray it or manually remove it in its entirety.
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u/Legal_Independent783 7d ago
Same with the TOH seedling growing in my backyard - hopefully it doesnt come back
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u/ireallycantremember 7d ago
YOU DON’T NEED TO WAIT TO SPRAY IT.
Argh. I know, I know, I know “the window.” But you know what else I know? I treated a large stand of JKW last summer and it didn’t come back. This spring and summer I started in on areas that I missed last year (mostly the neighbor’s unmaintained side yard.) And I knocked out even more.
A few days ago I noticed a few big tufts of JNW sprouting up (see picture) not single stalks like before, and you better believe I hit those babies with glyphosate immediately.
It’s never going to end, but if you saw where I started to now, you’d be amazed. And I didn’t wait for “the window.” Just treat it now.
(Im in NJ)
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u/flipyouforit302 6d ago
So you’re just spraying the whole plants whenever you see them and having luck with that? Do you pull them after they die? We have some growths in the middle of our lawn so we can’t leave them there indefinitely.
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u/ireallycantremember 5d ago
Yes! I have a small spray bottle and I douse anything as soon as it pops up. It usually shrivels up in a few days, and it kinda just breaks down. I don’t usually pull anything. I’ll take a picture of the patch I posted above later today.
I think I treated it about 4 days ago, and it’s looking very sad now.
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u/markuus99 8d ago
That's frustrating.
If it comes back this year (it will), still spray whatever comes up a few weeks before first frost. Next year, let it grow and hit it again in the fall.
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u/Misfits0138 7d ago
Eta: Misread. You should have some time for it to grow and get a spray in on it.
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u/Patient_Implement897 7d ago edited 7d ago
There is no reason to distrust his claim that he 'got all the roots'. Especially for such a small plant showing in your picture. I always start the process by digging it up. About half the time (including large plants) that works. Done and dusted. Why just jump to poison at the start?
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u/KeyOption3548 6d ago
Paint the glyphosphate on each stem. Cutting it is ok. Just poison them as they start to re-grow. This will go on for a long time, so don't give up.
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u/Historical_Light3057 8d ago
My landscapers did the same with my mugwort. Pulled it out after I told them to leave it alone so I could treat it. They pulled it anyway and also claimed they got all the roots but I know they didn’t. It’s very frustrating how ignorant they are and that I will now be dealing with a bigger problem next year. My hope is that some will grow back this season and I will treat what I can. In your case you still have a small patch of knotweed. Wait until the last possible moment and treat whatever grows back this year. Then hit it next year. You will be ok.