So You Want A Moss Garden?
Many of us want moss in our bonsai garden—a green carpet we can walk on to visit our royals on their posts and benches.
The bewildering array of mosses can leave us at a loss for what to use. There’s pincushion moss, a dome of soft green. Runner mosses that scamper over soil and logs. Dangling mosses that hang off branches. And the endearing silvery moss that pokes out of cracks in the sidewalk, Bryum argenteum.
Silver moss, Bryum argenteum, often found in sidewalks, and often used on bonsai pots
For years I attempted to grow a moss garden in the full sun. That usually doesn’t end well, and it didn’t in my case either. Eventually, with a better choice of moss, it worked with minimal maintenance.
The short-napped mosses—like Bryum argenteum—can work well for many moss gardens. I tried a few of them but the soggy soil in the wet season drowned it. The soft runner mosses which I found in forests did just as poorly, needing more shade.
The moss shown below—which looks like a miniature evergreen forest—finally solved my headache. It grows equally well in full sun or shade.
This is Polytrichum, an adaptable genus of mosses that do well in heavily-trafficked areas. You can walk on them without damage, which is perfect for bonsai posts that rise out of your moss garden. It’s too large a moss for most bonsai, though, so it’s better under your feet.
Polytrichum moss in my moss garden, in full sun
The apprenti in the garden a couple years back, presenting one of our moss beds. (Or more likely it was the azalea.)
To plant Polytrichum, collect patches of it from woods or open areas. Use bare ground, without nutrient amendments like compost or bagged potting mix. Mosses grow well on undisturbed, poor soils. Plant in the wet season, if you have one, to aid establishment. Avoid fertilizer as that just encourages weeds to outgrow the moss. And watering in the summer is often needed to prevent dead patches.
If you are lucky to have a dappled shady area, your choices of moss widen.
No matter what moss you plant, pulling weeds is the primary maintenance. (Preemergents may be used to control weeds in moss gardens—which prevents the seed radical and roots from forming—though beware of leaching into riparian areas where they can be toxic to fish and amphibians.)
Juniper Haircap Moss, Polytrichum juniperinum
Common Haircap Moss, Polytrichum commune. This and the previous moss are widespread throughout many continents in the world.