by Pete Morris – Club Member 11/2022
The art and practice of bonsai seems hardly a minimalist pursuit. Though the most graceful expressions of the form inspire a delicate balance, and the translation of wilderness to object can be incredibly meditative, the living relationship between flora and vessel proves contemplative, complex and horticulturally challenging. The process by which a tree becomes ‘settled’ in its pot is duration, manipulation, intense care, and symbiosis. Like moss to ruins, or rain to an abandoned bucket… One necessitates the other and vice versa.
Ceramics (an immense art form in and of itself) have their own distinct beauty and temperament. Ceramics are subjects of a lengthy geologic process made tactile and supple by sculpture and vitrification. A glazed pottery rings in an almost ancient frequency. The various colors may display traces of soot and fire or a gemmy luster, and the draw to them is universal, innate.
There are however, endless places and spaces a tree can grow, like high alpine boulder fields, desolate plateaus, eroded river gorges, or the seemingly impossible deserted phone booth. So, one might say that bonsai can be created with many types of containers and many different species. And we’ve seen it done and executed brilliantly.
Cement, because it is cheap, ubiquitous, and versatile, makes a great option for custom containers or slabs for bonsai. We can achieve the durability and function of a traditional ceramic pot and yet elaborate with many forms and experiment much more easily.
There’s a pleasant simplicity in the process as well… The general ratio is 1 part Portland cement: 1-part fine sand, and the basic shape can be formed with 1/8” inch wire mesh which will create a skeletal structure that provides rigidity and prevents cracking.
This is the method I’ve adopted and I like it because it’s an additive process whereby the application of the cement is relatively easy, and it allows me to add features and textures, after the initial shape comes together. There are other techniques such as casting or relief carving and none of them, I’d say are mutually exclusive. For instance, you may find yourself heavily thickening an area to create depth or a specific feature, and then scooping away pockets, or tooling in ledges or fissures. These are relief techniques.
One can also utilize molds for casting, whether it be sand, or a (plaster or synthetic) slump, hump or drape mold. Slump molds are often utilized with clay with which the thickness can be controlled by rolling slabs. Hump molds (the inverse, or negative space, of the desired object) are useful for casting cement. Sculptors may utilize a drape casting for a shallower form (such as a slab for bonsai!) by pre-drenching cloth in a wetter cement mix and ‘draping’ it over a mold.
Depending on the viscosity of your cement mix, it may also be necessary to combine techniques…For example; After composing my initial form, I often embed the mesh shape into a container or pile of fine sand so as not to lose too much material as I trowel it on. It’s a combination of a hump mold and a drape mold…The wire mesh structure is ‘draped’ over a hump ‘mold’ of fine sand. Once the cement coated wire mesh is cured enough to handle, it can be removed from the sand, brushed off and rearranged to accept more cement.
Our goal is to first encase the wire mesh in an initial layer. It may be necessary to do this sequentially, first leaving the outer shell or side of the form to mostly cure, before flipping it over to infill the rest. Cure times will vary and it’s best to postpone a bone dry state until you feel you’ve reached a final product and are happy with the design and function of the slab or vessel. Consider leaving more drainage holes or tie down points, especially if the form becomes more complex!!! A spray bottle or mist charged hose is handy to keep your layers lightly moist and pliable enough to accept more mix.
Features can then be added safely up to 3/4” thick and will otherwise need more mesh reinforcement, especially if dramatically extending beyond the main shape. When finished, allow the sculpture to cure completely for as long as possible in a dry place. If in a heated environment this could mean 24-72 hours. After it’s completely dry and stone hard, with a subtle ping noise to it when tapped, the finished pot or slab needs to soak in water. I prefer to set it in the rain where I can ponder it, or near my trees where I can admire it as I water.
Soaking achieves two things…. It will clean off excess grit, but more importantly, it will leach out any caustic minerals or alkalinity from the cement which could potentially harm the planting or chemically react to certain fertilizers. After the soaking process, when the container is again bone dry, it can be left unfinished or painted with acrylic. There are also dye colorants which can be added to your mixes. I choose not to paint the interior, or the bottom, so as to avoid contact with roots, but also to retain porosity and moisture retention…. And we’re ready to pot!!!
Other tools to have on hand…
Mixing tray, sand bed, gloves, various shapes/sizes of trowels, scrap plywood & sawhorses (work bench), buckets for mixing and washing, various brushes, chop sticks, spoons/forks/knives…texture!, tin snips or metal sheers, charged garden hose…
Other considerations…
Geology – riverine, coastal, mountainous, terrace, plain, island, canyon, cave, cliff, arch
Mineralogy or fibrous/organic – sedimentary, metamorphic, igneous
Will the container be species specific? – drainage!!! shape, aeration, substrate
Specimen/Age – refined or in training, trunk movement, root structure!!!
Thanks for reading! Cheers!
To building worlds inside of worlds;)
Here’s some links to check out…
Concrete bonsai pots
Bonsai Pots – Atelier Bonsai Element – Erik Krizovensky
“Unique handcrafted bonsai pots made from frost-resistant cement. Erik is a bonsai artist himself, as well as the creator of exceptional bonsai pots, with an extremely rustic feel.”