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Just wondering what this broad-leaf grass is called and how I can safety remove it from my "Blue Couch" (Digitaria didactyla) lawn. I've seen it take over many people's yards but have never known what it is and why it's there. Please help me sort this invader out.

Another question while I'm at it: Why does my lawn tend to die along the brick wall of my house or be easily invaded by this mystery grass? Is it the dryness of the soil from the heat of the bricks? It seems to get plenty of sun. I live in South East Queensland.

broadleaf weed growing in barren area

broadleaf weed growing dense in shaded area

where the weed meets the blue couch grass

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    Welcome to G&L.SE. Would you mind separating out your second question? It will help you to get better answer. And most likely more reputation points as well. – Patrick B. Aug 12 '15 at 12:46
  • As for your dry patches a good old hand watering with a wetter aid should help. Wetter will let the water penetrate deeper into the soil, if you can apply it evenly to your whole lawn. An evenly spread fertiliser will help boost your lawns as well slow release of course – user13450 Nov 21 '15 at 11:52
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Well I can answer the second part of your question - yes, the heat from the wall is a factor, along with rainshadow, meaning the bit directly below the wall may not be receiving any rain at all when it rains, or much less than the rest of the area.

As for the 'problem' grass, what I can see in the top picture is a few sparse blades sticking out of what appears to be sand, and sand with a hole in it where either something's been inserted, or an insect is entering and exiting. If the second photo is supposed to be showing a different type of grass, I'm afraid I actually can't see any difference other than a thicker covering, so a bit of clarification and possibly more pictures showing the grass you want to keep and a bigger patch of the grass you don't. Usually, though, when a weed grass invades a lawn, there is no easy treatment plan - any weedkillers designed for use on lawns are meant to kill broadleaved invaders, not rogue grasses, so the answer has to be the old fashioned one - dig out the areas of rogue grass and replace either by seeding or turfing the patches.

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The grass in question is called Broadleaf Carpet Grass. It thrives in moist conditions and can tolerate 50% shade. It doesn't seem to be tolerating glyphosate though!

http://www.nt.gov.au/d/Content/File/p/Garden/487.pdf

  • Do not apply glyphosate to your lawn as it kills all grass types. I find a broadleaf weeder seems to knock it about and a repeat spray within 2 weeks helps – user13450 Nov 21 '15 at 11:21

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