When & how to handle nutsedge in ~30day old reno

[wis99ski]

I am doing a small reno (my 3rd) for a family member and overall great weed kill but it appears some nutsedge popped up 2 weeks in. It is the most prevalent around the impact sprinklers. Can someone recommend when and how to handle it on a new reno? Im thinking it should start to be slowing this time of year but there is one spot 10'x10' that it thickened up which has me slightly concerned.

[ken-n-nancy]

First question is whether or not it is actually nutsedge.

The definitive way to identify nutsedge is the triangular stem, just above the roots and before the leaves all separate from the stem. You can feel this by rolling the stem in your fingers or by cutting a cross-section of the stem. See the photo below for a cut cross-section of the stem. (Photo from the nutsedge page at Michigan State University: https://www.canr.msu.edu/resources/yellow_nutsedge)



In a reno, my first inclination with any new weed is to hand-pull. It immediately addresses the problem of contention with the baby grass seedlings, even if the weed comes back in the future. At least when it comes back, it will need to do so in established grass and won't be stealing nutrients from baby grass seedlings.

However, if you have a patch which is growing quickly, it is probably coming from tubers (nutlets) on the roots of old nutsedge plants. My inclination is still to hand-pull a few and see if they have very small, immature root systems (in which case they came from seed) or have more significant roots, potentially even ones showing "nutlets" on the roots (google image search can help you find pics of these).

If immature root systems, just hand pull the rest and be done with it.

If they came from nutlets, then you've got a more long-term issue on your hands. I'd be torn between (a) hand-pulling them anyway, to end their interference with the baby grass, and then deal with more nutsedge next spring after the grass is stronger, or (b) hand-painting the nutsedge with glyphosate to eliminate them without adversely affecting the seedlings.

Tenacity is labelled to control nutsedge, but shouldn't be sprayed on baby grass until 30 days after germination. Personally, I wouldn't want to wait 2 weeks.

Anyway, sorry I don't have a definitive answer for you, but the above reasoning is what would go through my head if I were in your situation.

Fortunately, I haven't seen any nutsedge outbreaks in our ongoing renovation!
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[KBGkicksazz]

I have a similar problem in my front yard where irrigation went in, builder made trenches with equipment then filled with soil and voila nutsedge appeared.

Once the grass is mowing height and it gets a true cut my recommendation is to use sledgehammer or prosedge. They are the same active ingredient just different conpanies make it. It’s not a very harsh herbicide but it nails sedge very well.

I’m not one who like to mess with pulling sedge as even one nutlet remains and the sedge returns. And god help you once they get in a shrub bed.

I will be spraying my yard this Saturday as I have to wrap up my lawn activity for 2018 due to upcoming surgery that will take me out of action for a while so I’ll take pictures of before and after of the sedge slaughter.

My last house I got invaded with sedge and wish I had used herbicide instead of pulling.

[wis99ski]

Thanks for the great reply. I am hesitant to hand pull it because it will probably pull multiple young kbg seedlings out. If it continues to get "maturely' tall and not slow down I will stunt it with tenacity and hand paint as much as I can with glypho. I am thinking about hitting with sedge ender etc BUT am not sure if its safe for 30+ day old kbg..

[ken-n-nancy]

I am thinking about hitting with sedge ender etc BUT am not sure if its safe for 30+ day old kbg..

Make sure you read the label before applying Sedge Ender. I used that on my lawn once and was surprised how tough it was on the mature grass!

I think Sedge Ender (if using the Bonide product) also contains a pre-emergent in it. That might not be good for your grass seedlings, either.

In any case, the product label is your best source of info for your specific product.

[KBGkicksazz]

I’ve never used the Bonide product but looking at the label it contains prodiamine which is. PreM and not the right timing for that.

You can easily get sedgehammer or prosedge online. Even come in packets where one per gallon covers 1000 square ft.

Wait until the lawn is clearly mowing height and gets a proper cut before applying. Because we are into cooler weather (at least here in NH) it’s a little more forgiving but 30 days in on a reno with kbg is too soon for herbicide.

Labels usually say 2 mowings.

If it’s a few plants you can pluck them but if they are dotted around your yard expect to use sedgehammer either in few more weeks or next spring.

Thanks for the great reply. I am hesitant to hand pull it because it will probably pull multiple young kbg seedlings out. If it continues to get "maturely' tall and not slow down I will stunt it with tenacity and hand paint as much as I can with glypho. I am thinking about hitting with sedge ender etc BUT am not sure if its safe for 30+ day old kbg..

[HoosierLawnGnome]

Great question.

I use a prodcut with AI sulfentrazone, and as previously mentioned, it has a pre-emergent in it - not great for young turf. And yes, it makes a nice yellow spot while it does it's thing - but it works very well an it's all I use on sedges now. So, I don't think it would be my first choice on new plantings.

A better option for newer turf is good ol triclopyr. I find it is much gentler on newer seedlings. But, it takes diligence and repeat applications.

And don't forget about tenacity. Have you done the follow up app yet? Thta may knock it back some. Personally, I haven't had as good results with tenacity as tirclopyr or sulfentrazone.

If you're extremely concerned about damage to seedlings, you could always paint on the herbicide.

[KBGkicksazz]

Wis99 do you have pictures ? That helps give better advice.

Here is an example of my sedge dotted into areas where my builder added soil after I had already seeded in the spring. Everywhere that soil went I ended up with sedge and could not zap it as I had to repeat seed to get the whole lawn germinated. Only now can I start to fight it with sedgehammer.

[wis99ski]

Thanks for all the replies. I have not done the 2nd application of tenacity yet or started spoon feeding urea. I have used sedge ender in the past with good results on mature turf and recently used prosedge (Halosulfuron-methyl 75%) and boy was that rough on the kbg with the temps slightly elevated. I had some kill. At any rate let me grab some pics as I can walk lightly on the turf now that we are close to 30 days in.

[wis99ski]

Just sprayed tenacity at 6oz acre rate. I have a bunch of this around, which has white rhizome tillers that break off like sedge. This sedge?

[wis99ski]

Tenacity starting to do its job. The first urea feeding gave me about an inch or so of height. I threw some seed down in some bare areas and recommended the first cut at 2.5" today. The thin areas should spout and get to 2.5" before the end of fall and do fairly well into through the winter. I would always recommend following at least twice, as this is my 3rd reno and I only had enough time to fallow 1 of them which by the way has turned out the best.

[andy10917]

Just don't go wild on the Urea - stop when you hit the average first frost date, and let it naturally slow and then stop growing. Tender new growth forced by Urea makes for a problematic Spring...

[wis99ski]

Yes exactly