Hello Fellow Readers,
Last week’s column about removing moss from retaining walls (an idea I don’t favor as stark walls softened by mossy volunteers is magnificent) inspired questions about removing moss and lichen from tree trunks. More in worry over the health of the trees rather than their appearance. My own dear Curt was concerned for the maple tree near the screened porch adorned with a tapestry of powdery blue lichen interwoven with moss. Rest assured the presence of lichen and moss do not indicate the demise of the tree, though it’s true you see more of these mysterious organisms in mature forests because of the years they take to develop and thrive; especially so for lichen.
Unlike other opportunistic plants like wisteria and poison ivy vines here and kudzu smothering trees in the South, moss and lichen cause no harm. They’re merely seeking a structure to call home such as trunks, branches, rocks, even furniture where moisture and shade are plentiful. In fact, living hosts benefit from lichen and moss’s added barrier of protection.
According to Texas A&M AgriLife Extension Service, the part-fungi and part-algae or blue-green bacteria of lichen are not a “true species.” The fungal partner relies on the “photosynthetic products provided by the algae or bacteria” resulting in a resilient combo of algae and fungi “that is practically self-sufficient.” It often takes years for lichen to create a cover over bark which can live for hundreds of years giving our beloved maple an old-world charm.
There’s an old wives’ tale that moss grows on the north side of the tree which is not true. In fact, moss often colonizes all around trunks close to the forest floor or shady spots of lawns because of the moisture from constant ground evaporation. And, the slant and fissures of bark are variables too where moisture is slower to drain or if the tree is in a thick forest of shade. Authorities such as Tristan Gooley, author of The Natural Navigator (2010), wouldn’t put the northside folklore in his top-twenty techniques list. Rather, he suggests a compass — which means, of course, learning to use one. Mind boggling to me; thank goodness for GPS technology. (Though frequented hiking spots along the AT often are without a cell signal. But there’s plenty of moss and serenity!)
For those of you that feel these natural fuzzy organisms compete with the beauty of the bark, last week’s water-only power washing technique at a low PSI may work, but only when the tree is dormant after the leaves drop. And be extra careful not to damage the bark which would encourage pathogens and other opportunistic campers that aren’t self-sufficient or as beautiful as moss and lichen. Garden Dilemmas? AskMaryStone@gmail.com