The Japanese juniper is a low-growing conifer. In the natural environment, this evergreen can reach mature heights up to 24 inches. This juniper is also a tolerant shrub that adapts well to drought conditions and most soil environments. The Japanese juniper's characteristics and preferences make it an excellent selection for bonsai and an ideal choice for the beginning enthusiast.
Place your Japanese juniper tree in a warm, sunny location. Choose a bright location that receives at least four to six hours of direct sunlight, as recommended by the Bonsai Gardener. Ensure that the location is well-ventilated and away from sources of direct temperature variations, such as drafty doorways, heating vents and air conditioners.
Irrigate your Japanese juniper bonsai tree deeply and allow your tree to dry out slightly between each irrigation. Water the bonsai thoroughly until the water flows evenly from the drainage container. If you are unsure if you are irrigating thoroughly, soak your tree. Place your tree in the sink and fill the sink with tepid water until the pot is completely covered with water. Allow your bonsai to rest in the sink, as recommended by NE Bonsai, until the bubbles no longer rise from the surface. Remove the juniper from the sink and allow it to rest until the water no longer flows from the drainage holes. Return the bonsai to its location. Check the soil between each irrigation, and only irrigate when the soil feels dry.
Feed your Japanese juniper bonsai about once a month throughout the growing season. Use a well-balanced, slow release fertilizer such as an 8-8-8 or 10-10-10 combination. Distribute the fertilizer evenly around the bonsai at half strength. Water the fertilizer thoroughly into the soil. Avoid fertilizing your bonsai during its winter dormancy period, as instructed by NE Bonsai.
Prune your Japanese juniper bonsai periodically throughout the growing season. Use sterile tweezers to remove any dead or dying needles from the bonsai. Remove needles throughout the tree's interior to thin out the area. This will increase the air circulation and light penetration throughout the tree, as explained by Bonsai4me.
Repot your Japanese juniper bonsai about every one to two years and always before the bonsai becomes root bound. Remove the tree from its container and inspect the roots for adverse health. Use sharp, sterile pruning shears or scissors to trim away any dead, dying or wilted roots. Remove about one-third of the root system's mass using a root hook, as instructed by Bonsai For Beginners.
Repot your bonsai in a fresh, clean container. Use a bonsai soil mixture or mix your own loam. Mix equal amounts of nutrient-rich soil, clean sand and perlite. Incorporate the mixture thoroughly for even drainage. Line the bottom third of the new container with a layer of soil. Position your Japanese juniper in the center of the container and fill the container with soil. Ensure that all of its roots are covered with soil, and then press the soil firmly around your bonsai to secure its upright position.