Japanese selkova, also called Zelkova serrata, is a deciduous tree and a popular bonsai choice. In the winter, this plant pushes out small, fragrant, green leaves which turn golden or bronze in the autumn. This plant is hardy in USDA Zones 5 to 9, which means it can survive in areas where the temperature stays above -10 degrees Fahrenheit. Knowledge of how to care for this bonsai will help you produce an attractive and unique addition to your home.
Plant the Japanese zelkova bonsai in good-quality, well-drained potting soil and a pot with drainage holes in the bottom. Place the plant outdoors in full sun, as this tree requires lots of light and good air circulation.
Water the bonsai deeply throughout the growing season, allowing the top of the soil to dry slightly between waterings. Japanese zelkova requires lots of water during this time to grow properly.
Prune new shoots of growth back to one or two leaves with pruning shears. This will keep the plant small enough to thrive in its pot.
Fertilize once monthly during the growing season with a general purpose houseplant fertilizer diluted by half. Try using a water-soluble fertilizer as this will decrease the risk of root burn.
Stop fertilizing in the fall so that plant can go dormant. Also decrease watering to about once a week or every two weeks. With extreme temperature fluctuations and snow, place the zelkova in a cold frame. Although it needs the cold dormancy and is a hardy bonsai, it does not do well against the elements.
Re-pot the zelkova into a slightly larger pot in the spring. Young zelkova plants require re-potting every year. After the age of three, however, they only need re-potting every two or three years.