These little trees are uninspiring quality rejects. With the use of a ceramic slab and a little imagination perhaps it is possible to make something interesting. Slab and rock planting by this method requires the use of Japanese keto-tsuchi or peat muck. The Keto allows the containment of loose soil whilst the trees establish themselves and their roots bind the soil together
Prepare the slab with attachment wires. Natural rock slabs can be drilled and rocks can have wires glued into place with epoxy resin.
Root prune and prepare the trees.
If the Keto is very wet a little akadama or fine kiryu dust can be kneaded into the mix. Knead the keto to make a soft sticky paste and apply a retaining wall to your slab. Smooth the inner edge into the stone.
Add in a layer of planting soil.
Carefully consider where you are going to use each tree. Fix the first one into place with the retaining wires.
Gradually add in the rest of the trees. Little groupings work well.
Finish securing all of the trees and add in your soil. Work well in-between the root balls with a chopstick. Build up the soil profile if required.
Using more keto and a steel spatula profile the soil surface. Spraying with water will prevent the keto from sticking to the spatula.
Cover the entire soil surface with thin moss. This is best collected from an old wall, roof or even the dusty corners of a public car park! Forest moss will quickly overwhelm the little trees. Prune the trees as required and water well. Leave in a sheltered spot for a few weeks until the trees show signs of life. You may need to loosely cover the surface with nylon mesh if blackbirds find your moss irresistible. Once established you can treat these types of planting in the same way as any other potted tree. When re-potting do not disassemble individual trees but treat as one.