Answer: That orange growth is lichen, not a rust pathogen. Lichen do not harm the tree or shrub in any way. They tend to grow only on that outer bark and stay there, not growing deeper into live ...

This photo shows a lichen growing on hickory tree bark. Folks sometimes become concerned when they notice strange gray-green patches on the trunk or branches of a tree. Should the growths be removed?

They grow on almost every plant that has bark. They don't hurt plants, but they can be an indicator that plants are not growing normally because they are stressed. Here are a couple of emails from a ...

Once upon a time, my street used to be loaded with towering, shade-providing tall trees. It was a gorgeous tree-lined street, similar to the reputable Tree City USA award-winning streets throughout ...

I know many of us want winter to come to an end, but I would like just one more good snowstorm. I love all seasons, but I need a little more of that winter bleakness in the woods, primarily to help me ...

Lichen grow harmlessly on tree trunks and no control is needed. In fact, presence of lichens on healthy trees should be welcomed as likely positive indicators of lower levels of air pollution and a ...

Over the course of many years working with trees, hundreds of people have asked me about “that stuff” growing on the bark, or hanging from the branches of trees. What is it? Is it a disease? Is it ...

A couple of people have recently asked if the grey moss-like growth on the limbs and twigs of their trees and shrubs is the primary source of their decline. Trees and shrubs often have this sporadic ...

The Bryologist, Vol. 107, No. 3 (Autumn, 2004), pp. 340-344 (5 pages) A comparison between lime (Tilia platyphyllos) and holly oak (Quercus ilex) as substrate trees for epiphytic lichens was carried ...