Native to Western Asia, the Japanese Zelkova (Zelkova serrata) resembles the English or American elm trees with its smooth, dark bark and frazzled branches. It does not experience the typical pest or disease problems common to other bonsai, which is one of the reasons why many people believe the hardy Zelkova is the best deciduous tree for bonsai. Proper care of the Zelkova bonsai is essential so it is healthy and lives for many years to decorate an indoor spot with its beauty.
Place the Zelkova bonsai in a spot that receives at least four hours of sunlight every day. Although adapted to cooler climates, Zelkova bonsai needs some sunlight to grow healthy.
Water the container only when the soil feels dry. Do not over-water, but add enough so the soil is evenly moist. Use a spray bottle or watering can to prevent wetting the leaves.
Fertilize two to three times a month between early spring to late fall. Select a well balanced (10-10-10) bonsai fertilizer that is milder than regular ones. Apply the fertilizer at half the recommended strength and distribute evenly. Water lightly to ensure it goes into the soil.
Re-pot a young Zelkova every year in spring, and an older one every two to three years, or when the container becomes too small. Remove the Zelkova from the current container and inspect the roots. Remove excess soil, and use sharp, clean scissors to snip dying, diseased or wilted roots off. Snip healthy, long roots to up to one-third of their length.
Fill a container slightly larger in size than the current one with two-thirds soil and one-thirds sand to create well-draining, loamy soil. Make sure the container has drainage holes in its base.
Wire the Zelkova in the summer to train it to grow in the desired shape. Wrap the trunk with aluminum wiring first, then the major and smaller branches. Do not wire too tight as you could injure the bonsai. Cut the wire off after six months or when it grows in the desired shape.
Prune the Zelkova bonsai in early spring to maintain shape. Trim branches and stems with clean pruning scissors, and pinch back leaves with your fingers. The classic look for the Zelkova is a crown atop the trunk.