Marvelous, Moisture-Loving Moss
by Pam Carlton
Broadcast 9.21 & 9.24.2021
Take a walk through the forest, or along a river or stream, and you will find moss. Now take a look around your neighborhood. You may need to look a little more closely but you will see moss there, too. Moss lives on the shady sides of tree trunks, on the roofs of the houses, and between the cracks of the sidewalk. These non-flowering plants are small and not very flashy, so they are often overlooked. That is, until they become a problem. I found moss in my yard recently and my first inclination was to get rid of it. Who wants moss taking over their nice grassy lawn? Then I read Gathering Moss by Robin Wall Kimmerer. This book gave me an understanding and appreciation for this amazing plant.
Kimmerer blends Indigenous understanding of nature with scientific knowledge. As an ecologist Kimmerer studies the way plants interact with each other and with humans. For millennia mosses have been used as insulation, diapers, and in many other ways that require absorption. I had to know more.
Moss is unique in what it doesn’t have. Unlike flowering plants, mosses don’t have roots or a vascular system to absorb and distribute water and nutrients throughout the plant. Instead of roots, they have rhizoids. Rhizoids allow the moss to attach to a substrate, but they don’t transfer water and nutrients. Instead this job is done by their leaves. In order to survive, mosses need to live in an ecosystem out of the wind and sun that allows water to collect on the plant. This is how mosses use their small size to their advantage. They live within the “boundary layer”—so named because of its location immediately above the earth’s surface where the air is very still and acts as an insulating layer. The boundary layer traps heat and moisture, providing the perfect environment for mosses.
With such strict requirements, you might think mosses would be unsuccessful, but the opposite is true. With approximately 12,000 known species, mosses inhabit almost every ecosystem across the globe. Montana hosts 137 true mosses from the division Bryophyta. They will fill in the spaces that are left when other plants get too big or lack the nutrients, moisture, or sunlight to survive. Mosses don’t usually outcompete these other plants. Instead, they are ready to take advantage of those spaces that other plants find inhospitable.
So, to get back to my lawn. The moss isn’t taking over or killing the grass. It is taking advantage of the spaces left by my already-dying lawn. Maybe it’s too moist and shady for grass to thrive and if I take out all of the moss I will just end up with a lawn full of bare patches—hardly an improvement!
Once I looked more closely at where the moss was located in my lawn—in a shady, moist area—I realized that maybe I could allow the moss to stay. I no longer wanted to rid my lawn of this amazing plant. The question was, how do I let the moss live and still have the lawn and garden I want? After reading through my gardening books I found other plants that thrive in wetter environments. I sketched out a plan to create little islands of moss-friendly ecosystems. I knew that I might still find moss in areas I didn’t want to see it, but now I would take a moment to think about why I was finding it and how I might work with it. As I worked on my plan, words from Gathering Moss came to mind. An Onondaga elder once explained to Robin Kimmerer that “plants come to us when they are needed. If we show them respect by using them and appreciating their gifts they will grow stronger.” As I show my respect and appreciation for moss I hope it grows stronger and my lawn is all the better for it.
Every week since 1991, Field Notes has inquired about Montana’s natural history. Field Notes are written by naturalists, students, and listeners about the puzzle-tree bark, eagle talons, woolly aphids, and giant puffballs of Western, Central and Southwestern Montana and aired weekly on Montana Public Radio.
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