Question: Please help! Our lawn is being invaded. I have attached a photograph of the culprit in the hope that you can identify it and suggest how we can get rid of it.
We have tried digging/slicing it out with a knife (it has short roots) and sprinkled a weed killer on but neither has worked. It likes water and looks rather like a pondweed... I would be grateful for your advice.
Answer: The unwelcome inhabitant of your lawn is liverwort (probably Marchantia) - the common name sounds as unpleasant as it is.
As you say, it thrives in damp, shady places where the soil is compacted.
A lawn mosskiller may give some control, but getting more light to the area and installing drainage if there is standing water, would also help. In small areas, you can use a garden fork to spike the ground 3-6ins deep every 4-6ins.
If the area is large, use a motorised lawn aerator from a hire shop. In spring, when light levels are higher, you can seed the bare patches.
If the lawn receives under half a day of sun, it will always be prone to moss and algae. Planting shade-tolerant plants may be more suitable.
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