Onuma Growing Technique

Bonsai Tonight Blog—Jonas Dupuich

As for the soil, Onuma prefers red lava rock (scoria) for every tree in the garden. Sometimes sharp sand was mixed in, but most of the soil was straight lava rock.

Once Onuma’s chojubai develop great trunks, he places them in colanders. As the colanders fill with roots, he stacks additional colanders or ceramic containers to give the roots plenty of space to grow. By encouraging the sacrificial roots to grow downward, the roots near the trunk remain small and in scale with the trunk.

If a small tree is planted directly into a larger container, the roots near the trunk can become coarse – an undesired result when creating small bonsai.

A ring of drainage screen (see below) is a great first “container” as it can be made in any shape or size to suit the development goals of the bonsai.

Bonsai Tonight (see link below)

Onuma’s maples follow a fairly traditional development approach: let branches run for a year or two before removing them and repeating the process the following year.

[After a low chop (~1”), let shoots grow out. Repeat for a few years. Then develop the trunk higher and later branches]