RHS Journals

The Garden
October 2000

Herbs as bonsai

Bonsai need not take the patience of a saint or require an appreciation of all things Japanese. With a little regular attention, plants more familiar in the herb garden can be transformed in a matter of months, as Jon Ardle found

The Japanese had several centuries’ head start on the rest of the world in discovering which of their native species are best suited to bonsai. However, aristocrats, like Acer palmatum (Japanese maple) and Pinus parviflora (white pine) are neither fast growing nor forgiving plants, and inexperienced or impatient growers would be advised to cut their teeth on less expensive, more freely available material.

The question of what makes a good plant for bonsai is being asked more and more as enthusiasts across the world apply the techniques to indigenous plants. Ideal species have relatively small leaves, adapt well to permanent container culture, are cheap and widely available, vigorous, and cope with variable conditions.But perhaps familiarity in the herb garden has bred contempt, for few Western growers seem to have tried to bonsai rosemary, lavender, thyme or other woody herbs. Their vigour is such that with the right material, a convincing tree-like form can be produced within one growing season. In addition, the prunings of culinary herbs such as thyme and rosemary need not be wasted since they can go straight into the pot.Picking the right plants
The average garden may already have suitable herbal candidates for bonsai; garden centres or nurseries are other sources. Good ‘potensai’ – plants with potential for bonsai – have the same characteristics regardless of species. The trunk should exhibit good ‘taper’ so it is wider at the base and narrower higher up. In mature trees, the lower branches are the heaviest, but in young plants upper branches are more vigorous, making selective pruning to redress the balance necessary. Surface roots, or ‘neabari’, also make a plant look older.

Perfect potensai are few and far between, so look for interesting trunk lines. It is easier to build a branch structure around a decent trunk, particularly with herbal species that form buds on old wood, than to shoehorn existing branches into an unsuitable style.