How to kill St. Augustine Grass w/o killing Bermuda

How to kill St. Augustine Grass w/o killing Bermuda

shelto – posted 02 July 2003 14:47

Our neighbor planted st augustine grass and it is slowly but surely invading our bermuda grass. How can we stop this invasion without killing our bermuda grass? I’ve heard that maybe over fertilizing might be the key. Any suggestions will be greatly appreciated.

Dchall_San_Antonio – posted 03 July 2003 11:33

Slowly but surely is the key for you. Keep your bermuda mowed low at about an inch to discourage the deep rooting of the St Aug. Then, since St Aug spreads with above-the-ground runners, you just have to be diligent about pulling those things up. One good pull should get you a long runner.

I would build a 4 inch wide concrete barrier, a curb, between the two yards. Then keep the curb on HIS side edged if he doesn’t do it for you.

ArcherB – posted 06 September 2004 11:54

I have the same problem. Unfortunately, a concrete barrier is not an option. I do pull as much of it out as I can, but I can’t be out there every day. I’ve literally pulled out enough to fill up half of our city issued large trashcan. Is there another way other than brute force?

Alex_in_FL – posted 08 September 2004 15:11

1. Spray with a product containing 2,4-D or 2,4-D and dicamba, or MSMA. Several products have a mixture that includes 2,4-D. Make sure 2,4-D is the top ingredient if you use these mixtures. The bermuda may become discolored slightly but should recover quickly.

2. This fall when bermuda goes dormant you can spray the St. Aug with roundup.

3. Keep the grass cut short (cut at about 0.75″ to 1″). This will enhance the bermuda and discourage the St. Augustine.

Good luck!


justinhahn – posted 19 September 2005 02:38

Does round-up kill the bermuda? i am currently trying to convert my st augustine yard to a bermuda yard, and it is a very slow process. i am in the south, TX, any tips?

QWERTY – posted 19 September 2005 09:31

Round up is nonselective herbicide. It kills everything where the green leaves/blades are.

Are you sure you want bermuda lawn? it’s a lot of work to keep them looking nice compared to St Aug. They need a lot of fertlizer, plenty of watering to stay green and level yard to cut one inch 2-3 times a week to keep it dense enough to choke out weeds. Reel mower cuts a lot better than rotary mower at that height.

St Aug cuts well with rotary mower and only have to cut once a week at 3-4 inches (they do much better at that height). Less watering once established. People cut them too low like they’re cutting bermuda which discourage deep root development and requires more watering. They’re much easier to control than bermuda if you want to plant flowers, maintain flower bed, mulch base for trees or shrubs or whatever. Bermuda will take over very quickly if you don’t do anything. They are that hard to get rid of.

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