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A good Bonsai specimen demonstrates a balance in its component roots, trunk, branches, and leaves, all integral to its design. The roots and basal trunk are considered key to achieving a superior bonsai.
Achieving a great bonsai tree with inferior rootage, above or below ground, is impossible. Whatever method you use, it takes several years to grow a good Nebari, and the only way to get one quickly is to pursue it from the start or when buying new plant stock.
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Introduction to Growing Exceptional Surface Roots (Nebari)
One component of bonsai cultivation that hasn’t changed much over the years is how the trees are styled. Different bonsai styles will appeal to different people.
Still, they should all share age, beauty, and maturity – a reflection of nature’s stately, character-filled tree.
A bonsai tree must appear old, and a well-styled tree will make you wonder how old it is since it simply looks that old. A bonsai should be stunning and aesthetically pleasing, embodying maturity, uniqueness, and ancient stature.
The Nebari surface roots are the most common part of a Bonsai that people associate with age.
We must understand that Nebari is more than surface roots; it also considers how a tree bursts from the base and clings to the soil. Nebari gives the Bonsai stability and significantly affects how old a tree appears.
When roots develop too quickly, they appear youthful, extend from the trunk, and even look artificial. Good Nebari only comes with time.
There shouldn’t be any spaces between the soil and the roots, and the thickness of the roots should generally be uniform.
By this, I mean that there shouldn’t be two or three incredibly thick roots and, let’s say, two very thin roots, all of which taper.
A nice taper may be achieved 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 several roots to help it appear anchored in the soil.
How to Create a Good Nebari from Cuttings
If you are growing trees from cuttings, then you have the ideal opportunity to create a good Nebari from the beginning. I start with stacks of cuttings that I pot up, but not all will be good.
While it is best to root quite a few so you have a choice, sort out the rubbish early so you aren’t wasting time and space once it is underway.
Select cuttings that have roots growing all around the base of the cutting and not just on one side, as is often the case.
The best Nebari grows from a cutting base, developed from adventurous buds 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. See my article on Growing a Bonsai – From Tree Cutting to Bonsai in 12 Years.
The ideal time to work on the Nebari is when repotting the tree or transplanting it from the ground or a training pot. In nature, Nebari is a result of the tree growing vertically and in girth.
The tree pushes upward while the roots around the base expand, developing a flared platform. Over time, the soil around the tree’s base gradually erodes, exposing the surface roots so we can see them.
If there is no visible Nebari on our trees, we can remove the topsoil around the base of our trees to expose the roots close to the surface, a simulation of years of erosion.
On the other hand, there might only be a few fine surface roots that will need to be encouraged to grow. The challenge is to view your tree as a whole, paying special attention to Nebari’s development.
Good Nebari is developed over time, but by paying close attention to the detail now, we can vastly improve our trees in a much shorter time.
Sometimes this will require major work, or as I mentioned before, it can be as simple as wedging two roots apart that are growing too close together.
Developing Nebari with Regular Root Pruning
Every time you repot a tree, you should cut out the huge roots developing vertically to direct growth to the sideward-growing roots.
By doing this, the roots will become thicker over time and eventually produce a Bonsai Nebari that looks natural.
When developing new material, I set my stock trees on a tile to force a tree’s roots to grow sideways. The same result can be obtained by cutting back on vertically expanding roots and directing energy toward horizontal roots, promoting Nebari development.
Developing Nebari Using Air Layering
Air layering involves converting aboveground growth to a rooting system. This can happen when a plant’s branches are buried underground. An example is a fallen tree.
The Raft, or Netsunagari style, depicts this well. In the realistic scenario, this style aims to imitate a woodland tree being blown over, shattering the branches on the downhill side.
The remaining branches (growing vertically from the undamaged side of the trunk) eventually grow to seem like new trees joined by the old trunk as roots form from the trunk lying on the soil.
When the trunk grows thicker, the stream of nutrients will decrease incrementally, forcing it to grow new roots just above the wire. The process is best done in the early growing season – spring.
Tachiagari means the lowest part of the trunk without branches, referring to the section of the base of bonsai trees from which a plant grows to become a trunk.
This portion in bonsai trees is important from the standpoint of Nebari (visible roots of a tree) firstly and tachiagari secondly. It is considered best for the trunk to emerge from the Nebari.
Next time you look at a picture of a Bonsai, look closely at the Nebari, use a magnifying glass if you want, and have a closer look.
When you are in nature, look at the surface roots of trees growing around you and take note of the difference between the ancient trees and the young ones.
Observe the details of the roots of a slanting tree and how it anchors itself on the opposite side. Get inspiration from nature and then work out how you will achieve it.