The literal meaning of Tamamono in Japanese is “round thing,” but as a garden term it refers to shrubs that are shaped in a semi-spherical way, like the azaleas shown in the photograph here. Tamamono are typically shaped with a set of shears and/or with hand-snips. Best results are produced this way and not with electric shears.
Tamamono is a term that should not be confused with O-Karikomi. Both refer to garden shrubs that are sheared , but O-karikomi are shrubs planted to form a mass, sometimes quite large, and are most notable for the long, gentle line they create. Tamamono on the other hand, form individual semi-spherical shapes, although one shape may be composed of three, four, five, or even seven shrubs. The key is that the shape is semi-spherical.
When done well, tamamono are symmetrical, with the sides sloping down to the ground. When done poorly, the shrub will look like a ball, with the bottom branches curving back in under the top. This is an effect that should be avoided.
The idea is to add a mass, like a boulder does, but of course softer, and to add a voluptuousness to the garden. If the composition is laid out well, tamamono will be located throughout the garden to offer continuity, and as a result the effect will be much more “crisp” then if there were only naturally-shaped shrubs and specimen trees. Of course the overall effect of the composition is taken into account. A tea garden, for example, may not be right, perhaps instead seeking to offer the more natural effect of a mountain path.
Tamamono is one useful planting technique that seems to work well in the West where architecture varies. This element can bring something even without a Japanese-style garden composition. Appropriate shrubs are azaleas, boxwoods, Japanese hollies, etc.