When bonsai exhibits come around, bonsai enthusiasts love moss. They drive around town with their eyes on gutters and puddles in hopes of finding patches that can be scraped up and used as top dressing for their trees. But when moss grows into pine bark, the story changes. The goal is to find a way to stop moss from deteriorating delicate bark found on pines, spruce, cedars and the like.
Too much moss on the trunk – the bark is in jeopardy
On a recent visit to California, Akio Kondo made a suggestion for stopping moss – dish soap. He suggested mixing one part dish soap with 10 parts water and brushing it directly onto the moss.
Will the soap hurt the tree? Will it discolor the bark? I don’t know. Does it actually kill the moss? Yes. I gave it a try using a fairly mild dish soap. The 1:10 mixture I used browned a bit of the moss but not the thicker patches. I found I needed a stronger mixture to kill more of the moss.
Painting soapy water on mossy pine bark
A thick patch of moss – this bit proved stubborn
Like so many things in life, prevention is key. Stopping moss before it takes hold is far easier than stopping moss that has covered the bark. A lot of moss grew on my trees this spring and summer when it was cool and cloudy, but the moss has slowed down a lot in the past couple of months as the sun finally came out. As the days get shorter, I’ll be sure to keep some soap close at hand.
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Jonas, i have also found that vinegar works both quickly and well on even thich patches or moss.
I really like the look of some lichen on pine trunks but as you have pointed out a thicker covering of moist moss can really damage old bark.
“Jonas, i have also found that vinegar works both quickly and well on even thich patches or moss.”
Yep, me too. And here in the rain forest it’s moss city!
Howard Smith says
Are there any advantages of the dish soap method over the spray vinegar method? Besides the obvious nobody wants their pinus smelling like vinegar.
Hi Howard, smell is one big benefit that comes to mind, and Akio may have suggested the moss wouldn’t grow back as quickly when stopped by soap. Time will tell.