Magnolia stellata 'Rosea'

Algae growing all over my magnolia, help!?

Looks like lichen to me?

I think you're right. Apparently it thrives in unpolluted /clean air

But I read it's not harmful to my tree phew! Thank you @brightcolours I should know the difference between algae and lichen 😁 oops!

Yes, a good sign! Tried to paste some info and a link in earlier but couldn't. "Algae, lichens and moss are non-parasitic plant-like organisms that colonise bark, rock and other hard surfaces. Lichens and algae are often mistaken for a fungal disease but, fortunately, they do not harm plants on which they grow. Furthermore, they can give a mature look to a garden, preferring damp areas with minimal air movement."

"However, growths of algae, lichens and moss may be more common on plants lacking vigour, so their presence could indicate that attention is needed, particularly on old fruit trees and azaleas." https://www.rhs.org.uk/advice/profile?PID=411

Thank you Katie @brightcolours. So it may be lacking vigour...

Nah!! I'd say it's thriving in the bonnie fresh air!

You'll know more when you see how it flowers. But any shrub or tree does better when it's not competing with grass/lawn. So if you're at all worried I'd be removing it and mulching round the base of the tree.

Thank you Katie @brightcolours .... I might sound really stupid now. But I don't 'get' mulching... What does that do?

Retains moisture in the soil and (hopefully) discourages weeds, depending on what mulch you use.