Usnea Lichen Growing on Trees

Usnea Licken on Plum Trees

There has been a problem with the trees in the garden for some time now.

So I decided to do some study about this lichen, which I did not know the name of when I started researching.

Having researched this subject thoroughly, I still believe it does kill trees that it host on, as I have the proof of dying trees for the last ten or more years.

Of all the sites I have visited they all say that lichen should be viewed positively, their presence tells us that we live in a healthy environment and they give any garden an established look.

It is said that “lichens prefer areas with clean air, so are more common in rural districts” that may be true as we live in the high country with bush growing all around us and very little traffic, so if Usnea is very sensitive to air pollution, especially sulfur dioxide, the air is clear of that.

There is a lot of lichen growing in the bush reserve which surrounds our farm, also which I consider isn’t good, the possums are coming from the bush into the garden, if it is spread by spores they will be carrying it on their feet, therefore, that will be settling the spores on the trees.

If not then how does it start growing?

It is said that its spread by the wind.

I have found out that this gray-green fuzzy stuff covering many of my trees is one of the gentlest yet strongest immune tonics in the herb world.

But that does not make me feel happy about this lichen as it is unsightly in the garden.

The growth of algae, lichens, and moss may be more common on plants lacking vigor, so their presence could indicate that attention is needed, particularly on old fruit trees, in saying that this, the photo below was a very health plum tree until the lichen start taking over and it died.

Dead Plum Tree

Dead Plum Tree

Three Questions I have researched about Old Mans Beard – Usnea

  • What is Usnea?

Usnea is a lichen which is an organism that has characteristics of a Fungus and Algae.

  • How to tell if it is Usnea Lichen?

Elastic Thread in Usnea Lichen

Break the stalk of Usnea (thallus). If there is an elastic, white cord running down the center, then it is Usnea.

  • Does Usnea grow from spores?

By searching this question I have made the conclusion that it must be spores that nest onto the bark and germinate to start the beginning of the Usnea growth.

Lichen on Maple Tree

Lichen on  Maple Tree

By my study, everything is pointing against Usnea killing trees.

I do not agree.

My guess is lichen growing on trees is harmful to the trees, even though they are saying that the lichen does not extract nourishment from the trees when entering the inner bark and clinging to the tree branches where food is available from the tree.

My garden looks unsightly and I’m slowly removing the trees, but more seem to have lichen growing on them every month, I have tried pulling it off of them on the young trees but it continues on growing.

You can see by the photo below that Usnea does not need trees as a host as it is growing from an old basketball ring and surviving very well, it has the sun on it all day when the sun shines.

Lichen growing on Metal

Lichen growing on Metal.

The Cherry tree below is only about five years old and the lichen has already started growing on the trunk.

Cherry Tree

What are your thought’s about Usnea Lichen?

Have you seen it before, or do you have it growing where you live?

It hard to believe that it grows on sick or dying trees due to the pre-existing loss of canopy leaves.

If that is true it won’t be long before I have no trees.

Appreciate any comments.


  1. As an erstwhile amateur gardener i would say you have to go by what is happening to your plants in your garden. Your trees were fine until the usnea arrived, then they slowly died. My understanding and observation is that if the fungus, lichen and algae can not be halted, then only the removal of affected branches / shrubs / trees will stop it spreading to other plants. I don’t know what you do about the possums, unless you start trapping them – or do you need a permit for that ?

    Liked by 1 person

    • Thanks for commenting.
      Yes, we are allowed to poison and shot possums, and we do, you get rid of them, then it makes room for the next line of possum to come down from the bush ridges and take over the garden.
      The government thinks they can get rid of them by a certain year in the future (Not sure when) I think they may get a surprise how many there are.

      Liked by 1 person

  2. That is bad news, but maybe there’s a solution of natural ingredients to kill the lichen but not the tree. Good luck. You might call a botanist at the local or state university to see if they have ideas.

    Liked by 1 person

  3. In Latvia, we have been told that the bigger the lichen the fresher air. They are sensitive to pollution. In your picture – you must be living in the very clear area! Also. Our old oak trees (more than 200 years old) have lichen on them. No problem. And they are fed by air.

    Liked by 2 people

  4. I think the lichen are killing the trees. Usnea may have beneficial health benefits for humans but it doesn’t mean it is good for the poor trees. Keep searching for a way to rid the trees of it.

    Liked by 1 person

  5. We have lived in many places in New Zealand where this lichen is widespread. In my experience it has not harmed the trees it was on, but that’s not to say it won’t. There may be other factors at work

    Liked by 1 person

  6. I’ve seen this same Lichen choking out and killing a whole range of natives from Puhoi north to Whangarei and beyond. Everywhere I’ve looked says the same- that it’s a natural part of the forest community and not damaging to trees. But I too disagree!

    Liked by 1 person

    • Oh, thank you for agreeing with me, after many years of farming, I have seen what happens once it gets a hold of them, they are strangled lifeless and it’s getting worse. It is not good. Have a great day.


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