Finding the best solution for trees and people to live in harmony.

Does your tree have a virus?

Trees are precious, and one with a virus can present an emotional dilemma for the owner.  The virus will not usually kill your tree, but it may distort it in such a way that it becomes unsightly or loses vigor completely on one side.

Unfortunately, there is no cure for a virus, (think of Covid) A tee that is infected can be a problem for other trees in the garden, particularly those of the same genus. The virus can be transmitted by vectors such as biting and chewing insects for example aphids and mealybugs.

Some trees will show no visible signs of being infected and they are said to have a sleeping or latent virus, (again think of Covid in some people who are asymptomatic). It is often in times of stress when they are no longer able to cope e.g. drought or insect attack. Once infected most trees will have the virus for life. Waiting for a tree to recover can put other trees at risk and may take a lifetime.

I recently walked through a client’s garden where they had a newly planted grove of magnolias. The problem was, that one clearly had a virus and this was putting the other trees at risk. The trees were expensive to buy and the clients were reluctant to remove the tree.

So, what are the signs that your tree may have a virus?

  • Reduced vigor
  • Tree dieback.
  • Leaf distortions, including rolling and twisting.
  • Unusual patterns on the leaves.
  • Reduction of fruit produced or distorted fruit.
  • Branches may look dull and become fragile and break.
  • The trunk may look cracked or be flaky.


A good examination of the tree that is visibly infected is essential to ensure the symptoms are not mistaken for something else that could perhaps be treated. This is where your professional Arborist is important, as a clear diagnosis could dictate the fate of the tree.

If you are looking at purchasing new trees, e.g. fruit trees, check for good virus-resistant cultivars.

Interestingly some leaf variegation may be due to viral infection and could be considered desirable in some trees.

The best way to keep your tree virus-free is to keep it healthy by good management, including mulching around the tree, removing dead or broken branches to ensure quick efficient healing, and keeping an eye on any changes like a sudden influx of chewing insects.

If you are not sure of your tree’s general health, give us a call and we would be happy to have a chat.