Japanese Stiltgrass: Keep Your Eyes Open

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andy10917
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Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » May 11th, 2014, 12:32 pm

In the North, it's almost time for Japanese Stiltgrass to start making its appearance, as we move into mid-May and then June. You should be especially vigilant if your property borders on wooded areas.

Image

In many areas, Stiltgrass has moved from a weed that you've never heard of to a major problem over the past 10 years. It can invade a lawn or flower bed and completely crowd out everything in a couple of seasons. I have heard that it is now as far north as Massachusetts.

Having fought it and researched it in detail, the single best defensive act is to have a Pre-M shield in effect in May and June. If that doesn't work or you didn't have the Pre-M in effect, the only post-emergent herbicide that I know works is Fenoxaprop. It ain't cheap ($80+). I've done tests with Quinclorac, Tenacity, Certainty, etc on it, and they may injure it a little but do not work.

My tests are all on KBG. I have seen warnings about damage to Zoysia, and know that Fenoxaprop is used to control Bermudagrass. Do your own research if you have grasses other than KBG.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by JeremyFXDWG » May 12th, 2014, 9:19 pm

This is awful stuff I battled it last year.

Thanks for the heads up Andy.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » June 28th, 2014, 8:16 am

Now I'm totally confused. I had a serious incursion of Stiltgrass into the lawn last year (a couple of hundred square feet), and was armed to the teeth to take it on this year. And if anything, the Stiltgrass in the woods has gotten worse.

The ONLY thing I've used in the area of last year's incursion is Tenacity. No Pre-M's. And Tenacity clearly did not work on the Stiltgrass last year.

So why did the Stiltgrass stop right at the edge of the lawn this year? Not a bit in the lawn. I'm not complaining, but I hate to chalk things up to blind luck, and I hate things that I can't explain.

Is anyone else having success against Stiltgrass, without resorting to Fenoxaprop ("Acclaim") ??

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by Othertime » June 28th, 2014, 8:39 am

Been pulling it up in some random spots for a couple weeks now, small plants about a foot in height. I haven't the slightest clue how it got in some of my isolated beds from the woods. Pulls up easily, been rounding up the rest in wide open spots. Is RU ineffective????

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » June 28th, 2014, 8:45 am

No, RU works but isn't an optimal solution when it's embedded into the lawn (it does just fine when mowed).


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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by Othertime » June 28th, 2014, 10:03 am

andy10917 wrote:No, RU works but isn't an optimal solution when it's embedded into the lawn (it does just fine when mowed).
I fortunately do not have any in the grass, just mu mulch beds.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » June 28th, 2014, 10:25 am

Yeah, it's still in the flower beds, but stopped cold at the edge of the lawn. My question is WHY?

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Japanese Stiltgrass: Keep Your Eyes Open

Post by BoatDr » June 28th, 2014, 10:55 am

The two of you both been very aggressive with the mesotrione. Coincidence ?

Edit: whoops , I was thinking of D&TD. Sorry.

- Sent From My Sandlot.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » June 28th, 2014, 11:00 am

That would have been my idea, except that a controlled test of Tenacity on Stiltgrass last year was a big-time fail. Unless it is very susceptible when it is very young (a possibility), I'm still scratching my head...

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by BoatDrinksQ5 » June 28th, 2014, 6:44 pm

pH change or something out of its preferred range? or some other nutrient that is maybe a little higher/lower this year in the yard?

maybe the grass gods are looking kindly towards you because of your hardwork in the yard and forum? haha :)

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by crabgrass » June 30th, 2014, 1:03 am

What's the sun/shade differential? Didn't you take out some trees from last year. Maybe it prefers the shade of woods?

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Japanese Stiltgrass: Keep Your Eyes Open

Post by Tony! » July 16th, 2014, 10:05 pm

I just wanted to mention that I have this stuff in my weed pit back yard and been annoyed with it the last couple years. I back up to a wooded area.

I noticed that Bayer Crabgrass Killer for Lawns was actually labelled for stiltgrass control and main AI is fenoxaprop. I grabbed a RTS bottle for $15 and gave it a shot. It really smoked most of what it touched. Nice crispy brown. I let some of the plants get mature - about 1.5 feet tall and it took them all out.

Was a slow kill, about 2-3 weeks but none of those plants show recovery signs. Overall I would say it is very effective.

Btw Andy, it didn't seem to bother the hostas I mistakenly sprayed over top


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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by JeremyFXDWG » July 16th, 2014, 10:55 pm

Andy

I have been putting down the starter fertilizer with tenacity this year and have had the worst crop of stiltgrass ever. It seems tenacity has no effect on it here. I have been using acclaim on it per your recommendation.




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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » July 16th, 2014, 11:04 pm

The Tenacity I could have warned you about -- it was epic fail for me last year. I documented it here.

How is the Acclaim doing?

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by JeremyFXDWG » July 21st, 2014, 9:12 pm

The acclaim is working well. I need to respray what I missed and some that seemed to shrug it off. Most of it is turning brown and fading away.

I had no thought of tenacity doing anything to it I had put it down for other reasons.

I do thank you for the acclaim recommendation though as I could not find anything to selectively manage it.




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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » May 30th, 2018, 9:07 pm

Here's one that I'm waking up from its long annual nap -- it's right around now that we get "what is this stuff?" questions. It's made it all the way up the coast to northern MA, and the area affected is rapidly growing bigger every year.

Especially if you border a wooded area, keep your eyes peeled for the grass in the first posting of this thread.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by Green » May 30th, 2018, 10:58 pm

Andy, I swear I pulled a few out of the road gutter today, adjacent to crabgrass. I immediately thought this is what it was.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by Pway » June 1st, 2018, 3:06 pm

Thanks for the heads up reminder, Andy. You gave me the fenoxarop and PM multi year program a few years back and it does have the stiltgrass under control for the most part. But as you’ve said, in the wooded area it is lying in wait and ready to invade if I slip up. Also, the wooded area boarders a neighbor too and it is still prolific there (although I’ve lost my compass a couple times and accidentally treated a bit into their property.) Don’t think he’d mind at all, though. The place I play golf has significant wooded areas and other environmental areas left alone. It has really progressed significantly in those untreated areas. Amazingly, the grounds crew is able to keep it off the course itself. Japanese stiltgrass kind of reminds me of a non vine kudzu.

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by crabgrass1981 » June 2nd, 2018, 7:47 pm

I had it terrible last year (took over my whole back yard). This year I went very early and heavy with Preemergent (Feb), with a second application in Early May. I see it coming up along my fence and mulch beds - but nowhere in the lawn yet... am I likely safe at this point, or can it germinate throughout the summer?

I am assuming I should just nuke the young stuff with fenoxprop now?

Does this stuff spread while it’s growing? Or just take over if seeds are allowed to germinate?

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Re: Japanese Stiltgrass: Keep Your Eyes Open

Post by andy10917 » June 2nd, 2018, 10:25 pm

Yo're likely safe, but stay on any breakthroughs. To the best of my knowledge, it only spreads through seed.

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