Lichen

Although lichen is harmless, many people prefer not to have it growing on their trees, rocks and outdoor furniture.

Lichen have a range of shapes, sizes and colours and can live on a variety of surfaces. They grow very slowly and, if left, can live for hundreds of years. While it is not always welcome in the garden, the presence of lichen is an indication of good air quality.

Lichen isn’t a single organism, but a combination of fungi and algae or cyanobacteria. These organisms exist in a symbiotic, mutually beneficial relationship. The algae or cyanobacteria photosynthesise – producing food via the sun’s rays, which feeds the fungus. The fungus gathers nutrients and environmental moisture, passing it back to the algae or cyanobacteria.

Lichen are found on surfaces where other organisms struggle to survive, such as rocks, roofs, driveways, asphalt and tree bark. It thrives on tree bark which is exposed to harsh sunlight and rain. It can also be found on plants with sparse foliage, which allow the lichen access to the sun and moisture it needs to grow.

Prevention

Regular cleaning of exposed paths, driveways, roofs, or older structures on your property can help keep lichen at bay.
Feed and water plants well, as plant with sparse foliage can provide the ideal environment for lichen.

You can also gently scrub a trees bark to remove lichen with a clean moist rag or loofa, as their ‘roots’ do not penetrate the barn.
Do this with care, so you do not want to take any of the bark off.

Treatment on trees

In late autumn and winter you can use Lime Sulphur to eradicate lichen on deciduous trees only. Do not use it on evergreens, as they will defoliate (lose their leaves) and will not recover.

Treatment on surfaces

To control lichen on hard surfaces such as walls, driveways, paths and roofs use Weed Weapon Natural Power. For concrete paths, tiles, around potted plants and in lawns you can also use Yates Surrender.

Do not use these products on roofs that have a collection water system.

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