NATIVE GRASS HERBICIDE MIX UP - TECHNICAL QUESTION ON IMAZAPYR

[Sligh1]

This is a 1st for me. This question is VERY SPECIFIC & I've simply never dealt with this before!!!! So frustrating.
Have any of you ever messed with Imazapyr 4sl???? (Arsenal, stalker, etc)... Mainly used as long term ground clear, field prep & woody growth control.... https://alligare.com/wp-content/upl...-4-sl-specimen_mk-appr-072117-recd-051618.pdf

Had a little help & got sprayer filled up for me while I was putting down some fertilizer. I ordered some Imazapic for some Natives. Which I've used for years & love it. Very comfortable with it & one of my favorite herbicides for how well it works at intended use. I load up sprayer & hit 30 acres. Came back for something & did double-take on label & open jug sitting there...... IMAZAPYR!!!!!!!! is what they sent me instead. After I hit 30 acres (not in crp thank goodness but it's still mature natives). I about crapped my pants. I've never used Imazapyr ever so I grab the label immediately!!!.... long story short "kills everything!!!! Long term ground clearing". LOVELY!!!!!!!!!!!!!!!!!!!!!!!!!!!! I did use lower rate for Imazapyr, 10 oz per acre.

Here's my question.... Has anyone ever hit established natives with this? I'm gonna say the chance I get feedback here or experience is 1 in a million but still gonna ask.

I did have some glue-sniffing, paint huffing beauty spray growing natives last year on accident with Matador-s + GLY + 2,4-d & by MIRACLE, the natives bounced back just fine. That tells you how resilient natives are!!!!! My fear is Imazapyr could be more toxic to natives though & cook em. Yes, time will tell. Just seeing if anyone had any experience or insight here? & yes, learn from this and watch label close!

 

[JNRBRONC]

Natives meaning switchgrass?
https://digitalcommons.unl.edu/cgi/...tpsredir=1&article=2091&context=usdaarsfacpub


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[IowaBowHunter1983]

....that's bad shit. I believe that is the active ingredient in Ortho Groundclear that they market as "Season Lasting".

 

[Sligh1]

Natives- switch, Indian, BB, etc. thx on article!
Yepper!!! “Ortho Nuclear Bomb” or many other names. Just lovely!!!

 

[Duckriver]

Yes.. have sprayed it over bb, Indian and switch on purpose.....
All is not lost as the root systems of those native species are what helps the plant be so tuff. I actually have sprayed research plots with upwards of 70 ounces per acre of 2# formula. You used 10 ounces of 4#.....should yellow up. Will hit the forbs harder. But at your applied rate... I expect a little thinning. You likely helped the stand if it was a dense planting that needed a little thinning.
We actually use it a lot on crp to convert cp2 over to cp42. Aslo on strip herbicide on mid contract mgt.

 

[DannyBoy]

Yes.. have sprayed it over bb, Indian and switch on purpose.....
All is not lost as the root systems of those native species are what helps the plant be so tuff. I actually have sprayed research plots with upwards of 70 ounces per acre of 2# formula. You used 10 ounces of 4#.....should yellow up. Will hit the forbs harder. But at your applied rate... I expect a little thinning. You likely helped the stand if it was a dense planting that needed a little thinning.
We actually use it a lot on crp to convert cp2 over to cp42. Aslo on strip herbicide on mid contract mgt.

I would be really curious to hear more info on your experience and research. My experience is limited but I have not found natives in general to be very tolerable of imazapyr. But, maybe timing of application, rate, etc. are factors I could play with. What is your experience with residual and how long it needs to rest before it is safe to seed?

I manage some very dense native grass stands that I would love to add some diversity to. Many ways to go about that bust most are time and labor intensive.

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[Duckriver]

Left side has been treated. Right side has not. This is 2 growing seasons post treatment...today.
Last photo is same field last summer.

 

[Duckriver]

This is typically a last option for using imazapyr. But sometimes it's the best option when dealing with fields with trees, serecia lespedeza, johnsongrass,Bermuda, etc.
We are typically waiting 4 to 6 months after spraying before planting. August application typically. Planting the following spring in April or may. Sometimes we just stay on glyphosate all summer and wait till the next winter to dormant plant.
Imazapyr will thin grass but most stands have too thick grass anyway. Forbs will replace the grass typically.

 

[DannyBoy]

This is typically a last option for using imazapyr. But sometimes it's the best option when dealing with fields with trees, serecia lespedeza, johnsongrass,Bermuda, etc.
We are typically waiting 4 to 6 months after spraying before planting. August application typically. Planting the following spring in April or may. Sometimes we just stay on glyphosate all summer and wait till the next winter to dormant plant.
Imazapyr will thin grass but most stands have too thick grass anyway. Forbs will replace the grass typically.

Thanks for all that info, Duckriver. I like the looks of the sprayed plot vs. the control.

For the folks on this site who have CRP, when converting the cp2s to 42s, or any more diverse practice, is NRCS giving credit for already established grasses? Then interseeding forbs only? I am guessing no but great way to cut down on seed cost and not have to start over.

I will have to give your method to reduce grasses a shot. We have done some August haying of natives, which does a great job increasing forbs, but after 1 growing season the grasses take back over.

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[Sligh1]

Wow- that did work on lesperdeza!!! I spot that on right side. .

I did seed interseed some cp42- they wanted around 10 seeds per sq foot on interseed. Dunno on credit for grasses though if converting ??

 

[Sligh1]

Well - I think I got lucky. We all know natives are incredibly hard to kill. Applies to low rate Imazapyr as well! . 1st pic is sprayed on right, not sprayed on left. (This area had a low rate of native grass Plants) Then, pics in sprayed area of plant. I thought the natives would be burnt or discolored but they don’t appear damaged. Imazapyr be in soil a while so I’ll keep an eye on them but pleasantly surprised.