# Killing grass to mulch around tree



## Green (Dec 24, 2017)

Is it totally safe to use glyphosate with ammonium sulfate to kill the grass above the roots around a young tree to make a mulch circle? The tree dropped its leaves last week. Any issues? Just want to be certain and not damage it.


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## uts (Jul 8, 2019)

Green said:


> Is it totally safe to use glyphosate with ammonium sulfate to kill the grass above the roots around a young tree to make a mulch circle? The tree dropped its leaves last week. Any issues? Just want to be certain and not damage it.


I did this for my renovation for all the FF that was there. I did miss some which was dormant at that time but no issues. I did not have any root damage so I would think to look out for that so nothing gets directly into the plant.


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## ABC123 (Jul 14, 2017)

When I landscaped around my house I just put fabric down and then the mulched. Didnt have too much issues other than typical runners finding there way in from outside.


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## Green (Dec 24, 2017)

Would it be better to just dig the mulch ring and lay the mulch and wait until Spring to kill whatever grass pops up through the mulch? That way the mulch would protect the roots from the spray.

Then again, the tree is dormant now (buds forming, leaves gone). So would it be better now than in Spring?


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## uts (Jul 8, 2019)

Green said:


> Would it be better to just dig the mulch ring and lay the mulch and wait until Spring to kill whatever grass pops up through the mulch? That way the mulch would protect the roots from the spray.
> 
> Then again, the tree is dormant now (buds forming, leaves gone). So would it be better now than in Spring?


I would put mulch in the spring. From what was told to me snow cover does fade the mulch. Since the grass may not be totally dormant you could spray or pull up now as much as possible. I've never tried landscape fabric.


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## Green (Dec 24, 2017)

uts said:


> Green said:
> 
> 
> > Would it be better to just dig the mulch ring and lay the mulch and wait until Spring to kill whatever grass pops up through the mulch? That way the mulch would protect the roots from the spray.
> ...


I think I'm just going to do it as soon as I have time, glyphosate and all. The only thing I care about is not hurting the tree...doesn't matter if I need to spray again in the Spring.


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## Deadlawn (Sep 8, 2020)

ABC123 said:


> When I landscaped around my house I just put fabric down and then the mulched. Didnt have too much issues other than typical runners finding there way in from outside.


The problem with fabric is that it doesn't biodegrade. I prefer to use 2 layers of contractor paper under the mulch. The paper will eventually decompose and add organic matter.

If you decide to use glyphosate (I'm not a fan), paint it on the grass rather that spraying it. That way you will target plants exactly minimizing the environmental impact. It's not harmless to tree roots either.


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## Green (Dec 24, 2017)

Deadlawn said:


> ABC123 said:
> 
> 
> > When I landscaped around my house I just put fabric down and then the mulched. Didnt have too much issues other than typical runners finding there way in from outside.
> ...


Yeah, I'm not going to mess with fabric.

That is a good idea to paint the glyphosate. That way it'll mostly stay away from the roots because less will be used. Only issue is, I need a large brush to do it. Any ideas?

I also have ammonium nonanoate, but I won't use that as I know even less about its safety profile than glyphosate. The tree is important.

Another option is to mulch now but not kill the grass. Then in Spring only kill what pops through the mulch (whatever I can't pull out). Hopefully the mulch will kill the grass mostly and the mulch won't go al over the place as the grass moves during ground heaves. Does that sound like a viable option?


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## Deadlawn (Sep 8, 2020)

Green said:


> Another option is to mulch now but not kill the grass. Then in Spring only kill what pops through the mulch (whatever I can't pull out). Hopefully the mulch will kill the grass mostly and the mulch won't go al over the place as the grass moves during ground heaves. Does that sound like a viable option?


This is a viable option. You will definitely use less herbicide this way which makes it the "safer" method. I still like the "lasagna method" with the contractor paper as that leaves no light spaces for plants covered by the mulch. You will have fewer plants popping up through the mulch.


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## Cluelessone (Sep 23, 2020)

Can you leave it alone until spring? Especially with a young tree, I'd want whatever I could get for insulation on a young root system going into winter.


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## Green (Dec 24, 2017)

Cluelessone said:


> Can you leave it alone until spring? Especially with a young tree, I'd want whatever I could get for insulation on a young root system going into winter.


Yeah, speaking of insulation, I think I'm going to just add the mulch on top of the grass. Maybe that'll even do the trick and there won't be much grass left come April.


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## Bombers (Jul 14, 2020)

Green said:


> Deadlawn said:
> 
> 
> > ABC123 said:
> ...


First thought that comes to mind is a paint roller


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## Deadlawn (Sep 8, 2020)

Bombers said:


> Green said:
> 
> 
> > Deadlawn said:
> ...


I think a large brush (4 inch or more) would work better than a roller on weed grasses - paint it on in the direction of grass blades. Though a roller is more practical for a large area.


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## Green (Dec 24, 2017)

Thanks for the ideas, guys!


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