Can St. Augustine choke out nutsedge

keithmendez – posted 08 June 2009 09:09

I’m wondering if possible and probable. I noticed nutsedge sprouting up in different areas. I have set my mower to the highest setting so I’m hoping that by keeping the lawn well fertilized and not scalping it the St. Augustine will thicken up and choke the nutsedge. It has already done this to some dollarweed (to my amazement).

Thoughts?

Turfguy_UF – posted 08 June 2009 16:08

Raising your height of cut will actually cause the St. Augustine to thin out… if you have Floratam I would suggest mowing it at 3″ and do not remove more than 1/3 of the grass blades, which sounds like you already know that. Although the increase height can reduce the amount of light entering the lower canopy and that might help reduce nutsedge germination. But would still recommend keeping it at 3″.

Nutsedge is a tricky little guy as it has under ground tubers that allow it to go nuts. If you pull it it just pops off at the tuber and grows another one.

I can not say with 100% certainty that St. Augustine will choke out the nutsedge. It might reduce the amount of nutsedge but I would think getting a selective herbicide to remove the nutsedge would be your best bet.

A product out there called “SedgeHammer” will do the trick for you. Make sure your lawn is established before you use it.

Also make sure you read all the label instructions before ever applying a pesticide.

Side Note: Dollar weed is actually a sign of over watering or to much water in one area. It will correct itself if water is reduced or doesnt reach that area any more. Dollar weed is often associated with St. Augustine grass because it tends to get over watered. If yous see Dollar weed pop up again I would suggest cutting back on your irrigation, and monitoring the areas that had it.

TurfGuy

[This message has been edited by Turfguy_UF (edited 08 June 2009).]

Heyyou – posted 23 April 2010 10:20

Answer = no.

Try the segehammer. You can also use Image but it is not as effective (but does kill other weeds).