Bermuda Vs. St Augustine

rod – posted 25 June 2007 14:56

My entire lawn has St Augustine grass planted about 2 years ago, and I like it like that, since then some areas were “contaminated” with Bermuda, I’ve since then been pulling this Bermuda grass every other week, because if I stop doing this it will invade my entire lawn, at some point the Bermuda was winning and invading my St Augustine, but I’ve managed to stop this and keep the Bermuda in control, but I’ve got tired, and asked locally a way to control it, I was told that there is no way of killing the Bermuda with a herbicide and not damaging the St Augustine as both were classified as “thin leaf grass”, and was told to apply the herbicide with a “paint-brush” to the Bermuda leaf only, and after been killed the St Augustine grass will take over, and I’ve done so on the crowded areas, (didn’t care about broking my back as I was used to it by pulling the Bermuda grass very often), some of my lawn areas now look “spotty” and I am looking forward to see the area recovered, but in some other areas the Bermuda and St Augustine are so close together that don’t want to damage the St Augustine with this method.Do you know of any way/product to preferably kill or at least control the Bermuda grass without damaging my St Augustine grass?

TexanOne – posted 26 June 2007 02:38

There may be some herbicides that can temporarily retard the Bermudagrass from growing. However, St Augustine is naturally more aggressive than Bermudagrass in both full sun and part shade conditions, and you should not have to use any herbicides to keep Bermudagrass under control in St Augustine lawns.

The goal is to maintain the St Augustine so it will naturally overtake and control Bermudagrass without having to use any chemicals. There are several ways to do this:

– Cut the SA / Bermuda mix high – about 3” to 4” minimum. Bermuda hates high mowing and SA likes it. This will also cause the SA to quickly thicken and shade out the Bermuda.

– Feed sparingly – about 2 lbs of nitrogen / year maximum (one spring, one late summer feeding). SA needs less fertilizer than Bermuda to look good. Bermuda also slows down growth without high levels of nitrogen allowing the SA to take over. SA will continue normal growth and spread with reduced levels of soil nitrogen that causes Bermuda to slow dramatically.

– Keep the SA / Bermuda mix well watered. Bermuda is better adapted to drier conditions than SA. Under irrigation or regular rainfall, SA easily takes over Bermuda.

Overall, St Augustine has the ability to quickly send stolons (runners) up over the top of most grasses including Bermuda, eventually shading out and smothering competing grasses. Basically, the SA wins out because it has the ability to shade the lower growing Bermuda completely out of existence, but the key is cut the SA / Bermuda mix high.

Your chances of eliminating the Bermuda from your lawn are excellent without using any chemicals or herbicides at all. There are thousands of lawns in Texas that are 100% pure St Augustine that were once a mix of SA / Bermuda that did not have any herbicide treatments at all, simply by using the tips listed above.