Bonsai cultivation is the practice of growing miniature trees that capture the appearance of aged, full-sized specimens. This process requires starting with a plant that possesses the fundamental qualities for transformation. This starting material is known as pre-bonsai, signifying a tree in the initial stages of development. The journey begins with the selection and preparation of this foundational material before it is sculpted into a finished work of art.
Defining Pre-Bonsai Material
Pre-bonsai material is a plant cultivated specifically to possess a thick trunk and a vigorous root system, representing the potential for a future bonsai. It sits at an intermediate stage between newly propagated seedlings and a fully styled, mature bonsai. This material is typically grown in large containers or open ground to maximize growth and achieve an ample trunk diameter quickly. The primary goal is to establish a strong, healthy base that can endure the intensive pruning and shaping required later.
The material may have undergone some initial structural work, such as the first trunk chop or basic branch direction with wire, but it lacks the fine ramification of a finished tree. While it possesses the basic structure, the detailed silhouette and leaf density are not yet developed. Pre-bonsai is housed in a deep plastic pot or training box, allowing its roots and trunk to continue thickening, unlike a finished bonsai displayed in a shallow ceramic pot. This stage represents a significant time-saver for the enthusiast, bypassing the slow, multi-year process of growing a trunk from a tiny sapling.
Sources of Pre-Bonsai
Enthusiasts typically acquire pre-bonsai material through three primary avenues, each offering different levels of maturity and potential. The most accessible source is selecting suitable plants from general nursery stock, such as garden centers. These common landscape plants are chosen for their desirable trunk bases and branch structure, but require significant initial work, including heavy pruning and root preparation, to transition them into true pre-bonsai.
Another common source is material intentionally grown by specialist nurseries, often referred to as starter trees. These plants are grown in the ground or oversized pots for several years to develop thick trunks and low, well-positioned branches before being sold for styling. This material is generally more expensive but provides a head start in the development process.
The third method involves yamadori, which are trees collected from the wild, often exhibiting naturally aged, contorted trunks and dense wood due to harsh environmental conditions. Collecting yamadori requires proper legal permissions and significant expertise, as the material is often difficult to transplant and requires extensive aftercare to survive.
Key Characteristics to Look For
Selecting quality pre-bonsai material involves evaluating several physical features that determine its artistic potential. The most important feature is the nebari, or the surface root flare, which should radiate outward from the base of the trunk in a uniform, shallow, and radial pattern. A good nebari provides the illusion of age and stability, anchoring the miniature tree visually. Avoid plants where all roots plunge straight down, as this indicates a lack of proper root training.
Another fundamental feature is the trunk taper, which refers to the gradual reduction in thickness from the base to the apex. A smooth, pronounced taper is highly desirable, as it mimics the natural growth of a mature tree and adds visual drama. Material with reverse taper, where the trunk is thicker higher up than at the base, should be avoided, as this flaw is nearly impossible to correct over time.
Finally, examine the primary branch placement, looking for strong, well-positioned branches that are already low on the trunk and spaced evenly around the circumference. These existing branches will form the foundation of the tree’s final structure and canopy.
First Steps for Development and Care
Once pre-bonsai material is acquired, the focus must shift to ensuring its health and beginning the structural shaping process. The tree should be placed in a sheltered location for acclimation, allowing it to recover from the stress of transit or collection before any major work is undertaken. The first major step is often root work, which involves gently removing the plant and pruning back thick, circling roots to encourage a shallow, fibrous root system. This work is generally performed during the dormant season to minimize shock.
The next action is the first major structural prune, often referred to as a “trunk chop.” The main trunk is cut back aggressively to a lower, desired height to force new growth and establish the initial taper. This pruning dictates the future size and style of the bonsai and should be done with sharp tools to ensure clean, quick-healing wounds. Following pruning, copper or aluminum wire is applied to the primary branches and trunk to introduce movement and set the basic design lines.
After these initial procedures, the tree should be potted in a well-draining substrate, such as a mix of Akadama, pumice, and lava rock. Consistent water and light are then required to encourage vigorous recovery and growth.