Shade is harmful to Bermuda. Keep your SA cut high 3.5” to 4” and it will eventually smother the Bermuda. Cut your yard low and Bermuda wins. Atrazine is harmful to Bermuda so it will help the SA smother it out. Apply when to Bermuda is actively growing. Check the label but I believe that temps need to be below 90 and you can make only 2 apps of Atrazine at 8.6 oz/M.

 

No doubt, Bermuda does not like shade. Interested to see if this works. I have Bermuda grass where I live, and shade is about the only thing that stops it from growing, without using herbicide.

 

Check out this thread from last week about the same topic: Atrazine for Bermuda control in St Augustine

 

Ethofumesate is the main chemical that can fight Bermuda without harming St Augustine. Triazines such as Simazine or Atrazine are often mixed with Ethofumesate to get rid of Bermuda, and these applications can only be made up to two times per calendar year according to the Ethofumesate label. I'm personally not a fan of Triazines because of their leeching effects, aka their ability to move horizontally through the soil and affect non-target plants.

There's a new herbicide "safener" called Recognition being developed by Syngenta that should be out around spring. The safener is mixed with Fusilade, which can then be used to target Bermudagrasses and sedges in Zoysia and/or St Augustine. Fusilade by itself is harmful to St Augustine grass.

We don't know yet whether it will be sold pre-mixed, as a standalone product, or both, but you can search the forum for "Recognition" for more info.

 

I have a lawn service and they have identified the weed in my St Augustine grass as a Bermuda weed and they say they won't treat it or kill it as it is one of three weeds they won't mess with. The rep. does know why that is or what I may use to kill it.
Has anyone experienced this type of weed and how to get rid of it? It is expanding like crazy. I live in south west Florida.
thanks

For most people, the best thing to do is kill the area with glyphosate, cut it out, and then resod.

Bermuda thrives in sunny, fertilized areas, with a low height of cut.