Keep your Japanese maple bonsai in a warm, partially shaded location. Make sure that the location is well-ventilated and provides good protection from strong winds.
Water your Japanese maple bonsai deeply. Water your tree until the water flows evenly from the bottom of the container. Allow the bonsai to dry slightly between each irrigation but do not allow it to dry out completely. Adjust the irrigation levels for periods of drought and rainfall. Check the soil's moisture levels prior to each irrigation to avoid overwatering.
Feed your Japanese maple bonsai tree weekly throughout the spring. Use a well-balanced, water soluble fertilizer, as recommended by Bonsai4me and apply at half strength. Reduce the feedings to twice each month after the new growth, from late spring through late fall. Cease all fertilizer applications during the dormancy period.
Hard prune your Japanese maple bonsai during its dormancy periods, as recommended by Bonsai4me. Avoid spring pruning as the release of excessive sap through its wounds can result in adverse health for the bonsai. Use sharp, sterile pruning shears to complete the cuts. Remove any dead, dying or wilted branches and stems during the pruning process, as well as any unwanted branches and twigs.
Repot your Japanese maple tree bonsai every one to two years. Complete the process in the early spring, just before the growing season begins. Remove your maple bonsai from its container. Gently remove the excess soil from the root system.
Use a sterile root hook to remove about one third of the root system's mass from around the edges and bottom of the system, as explained by "Bonsai for Beginners." Use sharp, sterile pruning scissors to remove any dead, damaged or wilted roots from the root system. Sacrifice the fine feeder roots from the larger roots, as the fine roots provide regular nutrients and water to the tree.
Clean and sterile your potting container or choose a new container for the maple bonsai. Ensure that the chosen container is well-drained. Use clean, fresh soil to repot your bonsai, as well. Mix equal parts of nutrient rich soil, peat moss and organic compost to provide the bonsai with a nature, loamy environment.
Line the bottom of the container with a layer of soil mixture. Position your Japanese maple bonsai tree in the center of the container and fill the container with your soil mixture. Make sure that all of the roots are covered and press the soil firmly to secure your bonsai's position. Cover the surface of the newly planted tree with a layer of moss or stones, as explained by "Bonsai for Beginners," to protect the soil's moisture levels.