Propagation of Japanese Plum Bonsai Trees

Bonsai tree propagation takes a full season or two.

Japanese plum trees are members of the Prunus genus, along with other kinds of plums, cherries and blackthorn. Propagation from a seed is a long but rewarding process. Japanese plum bonsai trees are grown from regular Japanese plum tree seeds, as there is no such thing as a bonsai seed. Bonsai trees are cultivated to be the sizes and shapes that make them so popular, they do not grow that way naturally.

Seeds

The quality of the Japanese plum tree seed is important. Fruit tree seeds do not live as long as many vegetable or flower seeds, so it is best to use seeds that fell during the last growing season. One way to tell if seeds are still healthy is water immersion. Japanese plum seeds are dense enough to sink to the bottom if they are healthy, but they will float when dead. Seeds can be collected from other trees or purchased at a nursery or garden center.

Germination

Seed germination for the Prunus genus takes a full season, sometimes two. Germination happens through the heating and cooling of the seed through natural conditions, although there is a way to speed the process. Sow seeds outside in early autumn in a small container. They will go into dormancy over the winter, and the freezing and thawing of the ground will prepare the seed for a spring stratification. Small plants will begin to appear the first year, but it could take two or three years for the trunk to grow to its proper thickness.

Artificial Stratification

Artificial stratification can be accomplished when time is an issue. Soak the seeds in water for five to six hours, then transfer them to a damp plastic bag. Leave the plastic bag in a room temperature environment for three to four days. Place the seeds in a temperature controlled environment set at about 40 degrees F (4 degrees Celsius). Over the course of two weeks, slowly drop the temperature to freezing. Over the next two weeks, raise the temperature back to its original position. The seed will then be ready to plant.

Soil

When the seed is planted in the container, the soil should contain 2/3 compost and 1/3 potting soil and fill the container just over 1/2 way. Place the seed on top of the soil, then cover it with compost to three times the thickness of the seed. Cover the top of the soil with a thin layer of fine sand. Water the soil regularly so that it remains moist, but doesn't become completely saturated.

References

• Bonsai4Me: Prunus Species
• Bonsai Boy: All About Bonsai
• Bonsai4Me: Bonsai Basics -- Propagation From Seeds