Coarse grasses can quickly overrun fine turf, making it look patchy and spoiling the look of your lawn. These types of grasses are not easy to control and if allowed, can quickly invade large areas of your lawn.

Want to learn more about coarse grass in your lawn and how you can manage it? Let's find out.

Coarse grass

Image source: Wikimedia Commons



What are coarse grasses in a lawn?

Coarse grasses are simply patches of different grass species in a lawn. In a lawn that is free of coarse grasses, or weed grasses, it should not be possible to easily spot these different patches. Where different grasses are easily and clearly distinguishable, coarse grasses are more than likely present. Early identification and removal are vital, as there are no chemical controls.


What do coarse grasses look like?

Coarse grass is a lot easier to spot in a lawn than you might expect. Here are the things you should look out for:

  • Patchy grass with some displaying different colours and textures to the rest of the lawn
  • Flowering below the height of the cut, giving the lawn a peppered look
  • Leaf-sheaths that are a brown colour, giving the lawn a burnt appearance


What causes coarse grass?

Coarse grasses can appear as a result of various reasons. These are:

  1. By birds as seed or may appear through unsterilised loam used as lawn top-dressing.
  2. Coarse grass may be present in the original seed mixture and become visible only if the condition of your lawn starts to deteriorate. In a new or relatively new lawn, the seeds could have been dormant in the soil, springing up after the lawn was laid.
  3. Coarse grass can appear when the lawn suffers from excessive mowing, compaction or drought.
  4. Some fine grasses such as bents and fescues are prone to becoming scorched in cold weather conditions, stunting their growth and allowing coarse grass to take over.


Controlling coarse grass

There is no simple answer to how you control coarse grass in lawns, but there are commonly accepted suggestions that you can utilise. It's important to maintain and a consistent treatment programme in addition to regular watering and mowing, as this will help to thicken up the sward.

  • Before mowing your lawn, use a technique that involves slashing the coarse grass with an edging tool or a knife that cuts into the root system. Cut into the affected area in a crisscross fashion before you mow.
  • Once you've cut your grass, remove the debris and rake until you see enough soil to re-seed.
  • With the seed establishing at a good rate, this method should put the coarse grass under pressure to push it out of your lawn.

Other methods include:

  • Applying a spring lawn fertiliser that is high in nitrogen, in March. This will boost desirable lawn grasses as they come into growth.
  • Remove individual patches of weed grasses by hand.
  • For large problem areas, fork out the worst patches in September or October (adding soil to re-establish the level) and then re-seed with a finer lawn seed mixture or lay patches of new turf.
  • If infestation is extensive, control is much more difficult. Avoid frequent watering in dry summers, as meadow grass is shallow-rooting, so should be discouraged by drought.

When it comes to chemical controls, there are no selective weedkillers that can be used against coarse grasses in lawns without also killing the desirable grasses. Therefore, we recommend using only cultural methods when dealing with coarse grasses in your lawn.


If you think your lawn has fallen victim to coarse grass and you're looking for professional help and advice, the team here at Lawn & Weed Expert can help! Get in touch with us today to receive a FREE lawn survey where we can advise on the best course of action for you.

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