LICHENS, LIVERWORTS AND MOSS
Lichens, liverworts and moss are often found growing in damp or shady places in the garden on plants, soil and hard surfaces. They do not cause any harm, and can usually be tolerated as they can give a mature look. Although algae, lichens, liverworts and moss can be tolerated or even encouraged in a garden, they can make paths and lawns slippery, cut out light to greenhouses and evergreen leaves, and make ponds, borders and the top of containers unsightly so control is sometimes necessary.
Lichens are composite organisms: a fungus growing with an alga. There are more than 1,800 species of lichens in the British Isles. Some are very rare, restricted to specific sites but most gardens have at least a few.
Lichen growing on tree branches is often a worry to gardeners, but is rarely a problem.
Liverworts: these usually have a green, flattened, plate-like body and no leaves. A common example is Marchantia, which is often topped with umbrella-like sexual organs.
Moss: Moss that grows on the surface of compost is indicates a need for increased ventilation and more careful watering. Usually cushion-like.
Jeyes Fluid is suitable for controlling mould and algae on hard surface and disinfecting pots before use