Detailed Guide to Making a Broadleaf Mahonia Bonsai

  There are many varieties of broadleaf mahonia (Mahonia bealei). Common ones include the dense-spined broadleaf mahonia, whose leaf margins have denser spines, and the spineless broadleaf mahonia, whose leaf margins have no spines; these varieties are also often used to make bonsai. Mahonia has clustered stems, spreading branches and leaves, varied leaf shapes, and stays evergreen all year round. Especially when the old leaves turn orange-red alongside the newly sprouted emerald leaves, the red and green set each other off, making it very beautiful and elegant. It is a foliage bonsai suitable for viewing in all four seasons, and it also has value for its flowers and fruit.

  Propagation and Sourcing of Material:

  Mahonia can be propagated by cuttings, division, or sowing. Cutting propagation is divided into hardwood cuttings and softwood cuttings. Hardwood cuttings are best taken in early spring in March; cut 1- to 2-year-old vigorous branches as cuttings, 20 cm long, insert them as soon as they are cut, in a semi-shaded spot with moist, loose soil, or insert them into plain sand or vermiculite. Softwood cuttings can be taken during the plum rain season; cut fully developed, non-lignified semi-mature branches of the current year as cuttings, 15 cm long, and insert them in a sandy soil seedbed to a depth of 12 to 23 cm of the cutting. When inserting, first make holes in the seedbed with a bamboo chopstick, then insert the cutting, press the base firmly with your fingers so that the soil fits tightly around the cutting, water thoroughly, and set up a shade frame. During droughts and high temperatures, water frequently, spraying in the morning and evening with a fine-holed watering can to keep the soil moist. After about 50 days they will take root and sprout, and in the following spring they can be transplanted to grow into larger plants.

  Mahonia often grows wild in thickets on mountain slopes and by streams under the forest. You can select and dig up old stumps with unusual roots and trunks, cut back the branches and trunks, and first plant them in the ground to build up the stump. After new branches and leaves sprout, pot them up and shape them the following spring. In this way the trunk is thick and short, with many branches and an elegant posture, and a beautiful foliage bonsai can be made.

  Planting:

  Before planting, the plant should be soaked in clean water for about half an hour to improve the survival rate. When planting, it is best to coat the roots and stem base with mud slurry, then plant it in loose, breathable sandy soil. Afterward, keep the soil moist but not waterlogged, and spray the plant frequently to increase air humidity and ensure survival. Before long, many new buds will emerge at the bud eyes; you can select a few strong buds in ideal positions to keep and rub off the rest. Afterward, strengthen water and fertilizer management to make the plant grow vigorously. In the spring of the second year, shorten the branches that sprouted the previous year appropriately to encourage new vigorous branches.

  During the process of making a broadleaf mahonia bonsai, you can also cultivate directional buds. The method is: when a certain part of the plant needs a bud, spray it with water frequently, and before long a new bud will grow at that position.

  Pruning:

  Broadleaf mahonia grows rapidly. After 2 to 3 years of cultivation, the branches and trunks can be shortened, and some withered leaves should also be removed promptly to keep the tree shape attractive. If it is not grown as a fruit-viewing bonsai, the spent flowers should be cut off after flowering to avoid consuming too many nutrients and affecting growth.

  Shaping:

  Broadleaf mahonia can be processed into different forms of bonsai, such as forest style, double-trunk style, single-trunk style, slanting-trunk style, waterside style, and cascade style. The shaping method is mainly pruning, supplemented by wiring. Wiring should be done after the new branches have lignified, because at this time the branches are more flexible and not easy to break, whereas new branches are soft and brittle and very easy to break, so they are not wired for shaping. The main trunk and old branches are relatively brittle and hard, so they can only be pulled with metal wire or palm fiber within a certain range, or appropriately twisted for shaping, to avoid breaking the branches and trunk. Because its leaves are relatively large, the crown mostly adopts a natural style to express its natural, unrestrained, and spreading beauty.

  The processing of mahonia bonsai is similar to that of nandina (Nandina domestica), mainly relying on pruning and combining plantings, and generally not wiring. Processing is best done before spring sprouting, so that the branches and leaves are uneven from top to bottom, with a well-balanced density and a rich sense of layering. As for tree shapes, the multi-trunk-from-one-root style and the raised-root style are the most common, and there are also the combined-planting style and the straight-trunk style. For the multi-trunk-from-one-root style and the combined-planting style, attention must be paid to the variations in height, density, and front-to-back placement. For the raised-root style, the main root can be appropriately raised when planting, with soil mounded on the surface of the pot, and later, during watering, the mound of soil is gradually removed to expose the roots.

  Repotting:

  Repot once every spring before budding. The potting soil should be a sandy soil rich in humus, loose and breathable, with good drainage.