Plant Doctor Archive

Lichen on my feijoa trees

Our lovely row of feijoas have a lot of lichen covering their trunks and branches. The sprays available are all for deciduous trees. How can we get rid of this please?

Lichens on trees do not actually damage the plant — they are usually a symptom of aging — kind of like wrinkles! However, if you want to remove them, you can try one of the commercially available sprays. Most sprays that will kill off lichens are quite harsh and are not particularly good for plants, hence the instructions to use only on deciduous trees when they are dormant. You could try diluting one of the sprays and trying it on a patch of lichen, leaving it for a week or two and then checking to see what the effect was, both on the lichen and your feijoa tree. If all seems well, then continue the treatment. One other possibility is to cover the trunk for a while with shade cloth. The lichens you are talking about will be species that like a lot of sunlight. If you can cover them they will eventually die.

Advice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

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