Algae, Lichens and Liverwort

Algae, lichens and liverwort are a common sight in areas suffering from poor drainage, and in neglected lawns. Aside from the issue of appearance, algae, lichens and liverwort may prevent light from reaching the grass. 

Algae may appear as a green or black slime on the lawn, particularly on sparsely grassed areas with poor drainage, and under trees. Lawns that have become compacted, underfed or mown too closely are also prone to growth of algae. Regular aerating and top dressing with lawn sand will improve drainage and encourage growth of the grass and the roots. 

Lichen is a clear indication of poor growing conditions where the lawn may have too little drainage, too much shade and few nutrients. Scarifying, aeration and feeding will help address dry compacted soils, heavy thatch and drainage issues but where lichens have become well established over large areas replacement of the lawn may be the best option. 

Liverworts are found in areas of poor drainage and shade. Liverworts do not harm the grass and do not spread into areas of healthy grass. Regular aeration and feeding will help keep liverworts under control. If necessary, liverworts may be cut from the surface and following aeration the area may be reseeded.