Many bonsai hobbyists incorporate the use of moss as an integral component of a tree’s presentation. This article explores the benefits and cautions when using moss in bonsai, how to collect it, and how to apply it to a tree.
Nothing completes the authentic tree-in-miniature look of a bonsai quite like a velvety, emerald-green carpet of moss adorning the top of the soil. Used by hobbyists across the globe, moss is a perfect medium for creating the illusion of grass growing under a tree.
For root-over-rock bonsai or other styles that incorporate rocks in the planting, encouraging moss to grow directly on the rock contributes to a natural and authentic look.
Moss is also useful when putting together the small accent plantings that often accompany bonsai displays. Its miniature scale provides a perfect offset to the other small plants typically used for accents. Check out our article about accent plants to learn more about using them in bonsai.
Benefits of Moss
In addition to its aesthetic value, moss provides a number of practical and health benefits when used in bonsai.
Retains moisture. Not only does moss shield the bonsai soil surface from evaporation by sun and wind, it actually pulls water from the bottom of the pot upwards. This action helps balance the overall water content of the soil in which the tree lives. The roots stay more evenly moist and the pot needs watering less often.
Discourages animals. Birds looking for insects and rodents looking to bury a stash of food find the loose soil of a bonsai pot an easy target. A covering of moss over the soil makes the pot less apt to be disturbed.
Insulates the soil. Moss in a bonsai pot acts as an insulator, balancing the soil temperature. It helps keep the roots warmer in winter and cooler in summer.
Gives roots room to grow. Plants housed in a bonsai pot with a covering of moss over the soil tend to extend their roots into the soil surface directly under the moss. Without that moss blanket, the soil conditions near the top of the pot have too much light and air for roots to thrive. So, a moss topping can help the tree grow stronger by allowing it to amass more roots within the limited space of the bonsai pot.
Cautions When Using Moss
Now that we’ve covered the myriad benefits of using moss with bonsai, let’s look at a couple of precautions that beginners and even more seasoned hobbyists need to observe when using moss with their trees.
Keep moss off the tree. Moss on the soil, left unchecked, will expand to cover the exposed roots and trunk of the bonsai. Since moss retains moisture, allowing it to grow directly on the tree can cause wood rot. An easy way to remove moss from the trunk is to lightly brush just the moss with a bit of vinegar. Within a few days, the moss will die and can easily be brushed off.
Monitor soil moisture differently. Be aware that a covering of moss on a bonsai pot creates a very different soil and moisture environment for the tree’s roots than if there were no moss at all. Moss helps retain moisture, so the soil dries out more slowly. Also, since the moss lives on top the soil, it can begin to look dry even though there is still plenty of moisture deeper in the pot where your tree’s roots live.
These differences mean you need to take a little more care to guard against overwatering your bonsai tree. Too much water leads to root rot and the demise of the tree. Keeping a chopstick in the soil to check for moisture is one time-tested method of knowing when your bonsai needs water. If the moss is dry, but the tree isn’t, simply spritz the moss with water from a spray bottle.
How to Obtain Moss for Bonsai
The two primary ways to obtain moss for bonsai are to grow it or collect it. To grow moss from seed, cultivate it by scattering moss spores onto a thin layer of soil or other medium. Once the spores have germinated and grown into a healthy stand of moss, transplant it to the bonsai pot.
A big benefit of collecting moss is that the species gathered are ideally suited to the local environment. This makes them more likely to succeed when transplanted to bonsai pots. Collecting moss is free, easy, and fun. Just follow a few simple steps:
Tools to Take
Moss collecting requires a minimum of equipment. A paint scraper, putty knife or similar tool works well for removing moss from surfaces. Along with the scraper, grab a container to hold the moss you gather, add some damp paper towels or newspaper, and you’re good to go.
Where to Look
Moss grows in damp areas almost anywhere – in forests, backyards and in urban settings. Begin your quest by simply stepping outside your front or back door. Look for moss on growing on the ground, under bushes, and on tree roots near the ground.
However, some of the best places to look are rocks, sidewalks, bricks, tiles and walkways. Moss often grows between cracks in bricks and paver stones, as well as on chimneys and shady areas of buildings. Moss growing on these types of surfaces tends to be flat, which is ideally suited for use with bonsai.
Keep in mind that most bonsai trees require exposure to sunlight at least part of the day. Therefore, the mosses that work best are the varieties that thrive in, or at least tolerate, sunnier locations. Moss species that grow in shady spots may not survive in most bonsai pots.
How to Collect
When you find an attractive moss that you want to collect, simply use your scraper tool to lift clumps of it from the surface where it is growing. Moss does not have roots, so it’s quite easy to remove and place in your collection container.
While it’s nice to collect large intact clumps of moss, don’t worry if that proves difficult. You can effortlessly piece smaller clumps together when you apply the moss in a bonsai pot.
After collecting your moss, it can be easily stored if you aren’t using it immediately. Place it in a flat container, with or without a thin layer of soil underneath. Keep it in a damp and shady place and mist it daily. Alternatively, you can allow the moss to dry out in order to shred it as described below.
Using Moss in Bonsai
Hobbyists use two main techniques, direct placement and shredding, when adding moss to their bonsai pots.
Perhaps the easiest and simplest method for using moss is to place the clumps you’ve collected directly onto the soil of the bonsai pot. Soaking or misting moss makes it easier to place. Patch small clumps together to cover all or part of the pot. If you are short on moss and aesthetics are not a concern, you can leave some space between the clumps. The spaces will eventually close as the moss grows.
Another method favored by many hobbyists is to first dry and then shred the moss before adding it to the bonsai pot. This method works well when you don’t have enough of a nice variety of moss to cover the pot. Shredding allows you to stretch the limited amount of moss to cover all of the desired area.
Shred the moss by breaking it up into tiny pieces by hand, by grating it with a grater or wire mesh, or even by running it through a blender! Add a small amount of water to make a paste. Spread the grated moss paste evenly over the bonsai pot and keep it damp by frequent misting. At first, the pot will look less than attractive, but you’ll be rewarded in short order with a lovely moss carpet.
Additional Moss Tips
A few additional points about moss to keep in mind include:
Keep it short. Seek out low-growing species of moss with short fibers. Their compact growth habits will look better and stay neater in the bonsai pot.
Mixed Mosses. If you’ve collected more than one variety of moss, consider using a mix in your bonsai pot. The different textures can add variety and interest to the presentation.
Add Sphagnum. Some hobbyists add a layer of grated sphagnum moss to the pot, then place the decorative moss clumps or moss paste on top. The addition of sphagnum helps retain moisture to ensure the primary moss gets a healthy start.
Moss used in bonsai pots offers a number of health benefits for the tree in addition to enhancing its overall presentation. This article covered the easy process of obtaining moss and how to use it in the practice of bonsai.