Nebari (surface roots)
In the development of or selection of material to develop as bonsai, trunk qualities and nebari are the primary focus before branch or foliage development.
A very important aspect of a Bonsai is its Nebari (or: root-flare), the surface roots that provide visual balance to a tree. Ideally, the surface roots are visible on all sides of the trunk.
There shouldn’t be any spaces between the soil and the roots, and the thickness of the roots should generally be uniform.
Achieving a nice taper may be accomplished by “feathering” the severed area along its transition into the soil. In addition, a tree should have stable rootage, which means that it should be endowed with sufficient size, arrangement, and a number of roots to help it appear anchored in the soil.
The best Nebari grows from a cutting base, developed from adventurous buds found along the trunk or branch.
Growing trees in large training pots or on the ground will produce much better Nebari than in a Bonsai pot.
I’ve often been quite surprised at what’s right under the soil’s surface, often discovering an attractive Nebari already present.
Creating a Nebari can be done using two methods; by regularly pruning the downward growing roots or by applying a propagation technique; air layering. Both methods will be described in detail below.
Regular root pruning
By removing large vertically growing roots every time you repot a tree you replace growth to the sideward-growing roots. In doing so, over time these roots will grow thicker and ultimately create a natural looking Bonsai Nebari. Some growers place their trees on a stone when growing young material, to force a tree to grow its roots sidewards. But when repotting regularly, pruning the vertical growing roots should be enough to stimulate the surface roots.
The tourniquet method
This air layering method involves tightly wrapping copper wire around the base of the trunk, partially blocking the stream of nutrients from the roots. When the trunk grows thicker the stream of nutrients will decrease more and more, forcing it to grow new roots just above the wire. Apply a tourniquet during the spring. Read the step by step guide below for detailed information.
Early development from seedling to propagated branches using air-layering, results in a forced root network that radiates around the new trunk. These can be flared, pruned, and encouraged to be desired nebari.
Interesting nebari development during an air layering of a trunk too straight and long. Before and after—Instagram.
