If beauty is only skin deep, then why does the global cosmetic make up market top $40 Billion a year, and the overall cosmetic market combining surgery and clothing nearly reaches $2 Trillion a year. While reasons vary with individual, people alter their surface to either enhance their appearance, boost their confidence, to cover blemishes or imperfections, and express their creativity. It seems similar reasons apply to bonsai tree design. The texture, color, and shape of the surfaces of a bonsai presentation hold an important role in creating a display and should be planned from the beginning for good composition. There are several surfaces to consider in bonsai design: tree bark, foliage, container finish. This month we’ll focus on the soil surface.
Soil anchors the tree in the pot, provides transport medium for water and nourishment and creates a key appearance feature of the bonsai tree. Well draining soil, besides being the secret to bonsai cultivation forms a plane between the pot and trunk. With such a key role the soil surface needs attention offering lots of opportunities for creative expression.
The first point to consider is the esthetic role the soil surface plays. In a typical bonsai design the soil surface contributes to the overall illusion of a natural tree. But since bonsai soil is usually granular with relatively large particles the illusion of a natural setting could disappear. Consider if one were to scale up a 2 feet tall bonsai tree with 1/4 inch particle size soil to a full size 40 feet tall tree. At that ratio the 1/4 inch particles become 5 foot large boulders. This scale defect destroys the illusion. To solve this problem there are a few choices.
Use moss. Placing moss on the soil surface is a long held Japanese bonsai practice and it has become the de rigeur mantra of bonsai show organizers – “Trees must be mossed”. But why use moss? The reasons are the same as why people wear make up. First moss on a bonsai tree presentation enhances the appearance offering new colors, texture, shapes and interest to a composition. Second, moss can hide the large bonsai particles and maintain the scale of a natural tree. Since most moss has small size components, it adds to the illusion of a tree in a forest even though it is in pot. Moss can also protect the soil especially when watering. Careless application of a water stream can eject light-weight bonsai soil causing potential tree health issues. The moss acts as a blanket to protect the unwanted movement of soil particles.
Moss are non flowering vascular plants in the Bryophyte taxonomic division. There are many types of moss but in Brevard pin cushion moss is the best for bonsai. It is readily available, has the correct scale and forms little mounds ideal for a bonsai pot. Other mosses can work but if used as an accent as most moss can also have shaggy growth. Pay attention to scale. Spanish moss, ball moss, lichens and other epiphytes growing on living and dead trees are not Bryophytic moss and would be tough to work into a style. However, some people use bits of lichen interspersed within the ground moss as an accent piece.
Cultivating moss can pose a challenge. In the cool weather we experience now in Brevard county, proper watering will initiate a moss factory. The secret is to provide a fine mist of water over the soil. Moss spores are in the air and they will grow where the surface is damp. If your trees don’t have moss on them now here in January, then you need to evaluate your application of water. I take small quarter shaped pieces and move them from tree to tree and they will spread and cover the soil. Bonsai enthusiasts in drier climates use a fine layer of chopped up sphagnum moss under their moss to help the green moss retain moisture. I have found it unnecessary to do that in our humid climate. Some people suggest using buttermilk to encourage moss but I never bothered as I feel it might attract too many unwanted critters. Remove any moss that grows up the side of the tree. It can hide the tree’s taper and potentially harm the bark and texture. Use dilute vinegar and a soft brush to not hurt the bark texture. Keep in mind though water that grows moss will also encourage mold so regular cleaning of the mold needs to be part of the bonsai maintenance regime.
Moss isn’t the only answer, one could apply something else to the top of the soil. The design goal for the overall bonsai composition drives the decision. Top dressing of small particles can cover the larger particles and solve the problem of scale. Some people even apply a top dressing to help moss grow. I never liked the idea of a top dressing of fine particles as it could eventually clog the drainage of the larger particles below. Using top dressing only for a show though is fine. One could use different colors depending on the thematic statement. For example if one were using a desert tree, like a Dwarf Elephant Jade in a composition, it would be perfectly logical to create a tan desert like soil surface. For those with a more creative bent, other colors are possible. Keep in mind the proper scale and design concept. To get really creative one can use a membrane over the soil – a bonsai version of the artist Christo.
Another concept is to use some sort of artifact on the soil to help create the message. While I have never seen such a tactic in a Japanese show it is very common in Southern China where bonsai artist regularly use a figure on the bonsai soil (not just a landscape bonsai but tree bonsai). Some bonsai artists when creating a bonsai tree diorama add sculptural elements to enhance the soil and reinforce the design concept.
The final point is weeds – that is a wild plant growing where it is not wanted and in competition with bonsai. Don’t have them in your bonsai pot – especially for an exhibition. The only exceptions is if the design goal is to make an unkempt and messy statement. But even then the reason weeds detract from a bonsai as their scale is usually wrong so even unkept design goals need small weeds. The best way to avoid weeds is to limit organic components in the soil. And stay of top of them by pulling weeds out whenever they sprout in a bonsai tree. After all bonsai is a work of art and you don’t see mustard stains on paintings in museums so neither should you see unplanned weeds.
