The art and techniques of bonsai root shaping: a detailed explanation of the basics

First, root guiding

When shaping a young tree, cut off the main root to encourage lateral roots to develop and spread horizontally, so the tree can adapt to being grown in a relatively shallow pot. For a larger tree with thicker roots, the root system can be fixed with wire, with the shape determined by the shape of the pot, and planted in a relatively shallow pot. The root system can also be spread out horizontally, laid on a long wooden board and fixed in place, then planted into the soil together with the wooden board, so that the root system extends in a horizontal state. The root system cultivated by this method is suitable for planting in a shallow pot only 1-2 cm deep. Shanghai-style bonsai also uses this method.

Second, root-on-rock

Root-on-rock means attaching the tree's root system in the crevices of a rock, or threading the root system through the holes of a rock, forming a style in which the tree grows embracing the rock and passing through it, known as the "root-on-rock style." When shaping, choose the plant material and stone material well. The plant material should have well-developed, slender lateral roots. The stone should have a good form with a certain imposing presence, good texture, and many crevices and holes. Fix the tree's root system in the crevices or thread it through the holes and bury it in the soil, then use the method of raising the roots to gradually expose the root system of the root-on-rock portion together with the stone above the soil surface. Plant it into a suitable pot, and a root-on-rock bonsai is formed.

Third, inducing aerial roots

For banyan trees and other tree species that readily produce aerial roots, aerial roots can be induced artificially. The method is as follows: first, at the part of the branch where aerial roots are desired, tie a circle with wire to cut off the channel through which the plant transports nutrients downward, causing nutrients to accumulate at this spot. Then tie a gauze strip outside the metal ring and let it hang down to the pot surface, then place a bowl of clean water on the pot surface, immersing one end of the gauze in the clean water. Moisture seeps upward through the gauze surface to the metal ring, creating a highly humid environment that encourages downward-hanging aerial roots to develop there. Also note that before the metal ring sinks into the bark, it must be cut away in time to avoid sinking into the bark and affecting the tree's growth and ornamental value.

Fourth, exposed roots

Exposed roots, also called raising roots, means lifting part of the thick, strong lateral root system from the upper part of the roots above the soil surface. Its purpose is, first, to display an aged and antique appearance, and second, to make part of the roots hang and claw out, revealing the beauty of their posture. The methods are as follows:

Lifting method: also called the repotting method. This method involves, when repotting, planting the root system a little higher year by year, then washing away part of the soil with water, gradually exposing the upper root system above the soil surface. When necessary, the exposed roots should also be treated according to the requirements of the composition. For example, overly dense or surplus roots should be removed, or the distribution of thick roots appropriately adjusted.

Sand cultivation method: plant the tree in a relatively deep pot, fill the lower part with fertile soil and the upper part with river sand, guide the plant's absorbing roots into the lower part, then year by year remove the river sand from the upper part to expose the thick part of the main and lateral root system, then move it into an ordinary pot, and the upper roots are exposed. Root tidying is the same as above.

Sleeving method: this method is suitable when the height of the flower pot is insufficient. Around the upper part of the flower pot, add tiles or other materials, such as thin wooden boards or plastic sheets, to increase the height of the pot. When planting the tree, fill with soil, or fill the lower part with soil and the upper part with river sand. When the tree's absorbing roots extend into the bottom, gradually remove the upper soil or river sand and take away the tiles and other items to expose the upper root system. The sleeve-removal method created by Shanghai bonsai is the same as this.