Detailed Explanation of the Methods and Techniques for Creating Boxwood Bonsai

(I) Botanical Knowledge

Belongs to the family Buxaceae, genus Buxus. Evergreen shrub or small tree, with densely growing branches, four-angled twigs, and foliage clustered and rising upward. Leaves opposite, leathery, elliptical or obovate, apex rounded or slightly notched, base cuneate, surface bright green, underside yellow-green. Flowers clustered in leaf axils or at branch tips, opening in April, yellow-green. Capsule ovoid. Main species and varieties

1. Buxus bodinieri, also known as sparrow-tongue boxwood. Evergreen dwarf shrub, branches densely clustered. Leaves opposite, leathery, spatulate or oblanceolate, surface dark green and glossy.

2. Buxus sinica var. parvifolia, also known as pearl boxwood. Evergreen small shrub, with densely growing branches and foliage, short internodes, small glossy leaves. Graceful tree form, a precious species for making bonsai.

Boxwood is produced in the central provinces of China, growing wild in mountain areas below 1300 m elevation. It is widely planted in gardens or grown in pots for ornamental purposes throughout the Yangtze River basin and areas to its south.

It prefers light but also tolerates slight shade, is relatively cold-hardy, and thrives in fertile, moist, loose soil. It adapts to acidic, neutral, or slightly alkaline soil. It grows slowly, has strong sprouting ability, and tolerates pruning well.

(II) Material Collection and Propagation Measures

Artificial propagation: Usually propagated by sowing or cuttings. For sowing, harvest ripe fruits in July, spread them out to dry in the sun, then thresh to extract seeds and store them in bags. Sow in winter or early spring; if sown later than March, few seedlings emerge that year, and most will not germinate and emerge until the following year. Before sowing, soak the seeds in 40°C warm water for a day and night (allowing it to cool naturally), then dry them and sow. The seedbed soil should be fertile, loose sandy loam. Drill-sow with a row spacing of 15-20 cm, a sowing width of 5 cm, and a sowing furrow depth of 2 cm. After sowing, cover with 1 cm of burnt soil, then cover with rice straw. After seedlings emerge, remove the straw promptly and set up a shade frame. Strengthen management during the seedling stage: weed, loosen the soil, water frequently to keep the soil moist, and apply dilute cake fertilizer water. Remove the shade frame in September and leave the seedlings in the bed for another year before transplanting.

Cutting propagation: Best carried out during the plum rain season. Select semi-lignified healthy branches as cuttings, 10-12 cm long, with a heel at the base, leaving 5-6 pairs of leaves on the upper part. Insert to a depth of 1/2 to 2/3, with a plant and row spacing of 6 x 10 cm. After inserting, press the soil firm, water thoroughly, set up a shade frame, and spray water frequently to keep the soil moist. During hot weather, watering even more frequently is needed. Remove the shade frame in September-October and leave in the bed for another year before transplanting. Boxwood can also be propagated by thick-trunk cuttings: cut relatively thick branches from clustered plants, leave several whorls of branches and foliage on top, bury the trunk portion entirely in yellow sand or vermiculite with the branches and foliage exposed, water frequently to keep moist, and roots will form after half a year.

Collection from the wild: In subtropical mountain areas, boxwood is mostly scattered under mixed forests or along ditches at forest edges. In barren areas with exposed rock, boxwood grows short and small with dense branches and foliage; after collection, potting, processing, and shaping, it often becomes a fine bonsai specimen. Buxus sinica var. parvifolia in the middle and upper parts of mountains at 1300-1800 m elevation in East China often grows in patches, forming evergreen shrublands dominated by pearl boxwood. It also grows abundantly in mountain rock crevices, with thick, short trunks and dense small leaves, making it most suitable for bonsai. However, pearl boxwood is a high-mountain tree species requiring a cool, moist climate and acidic sandy loam. Wild stumps or seedlings collected should be cultivated with plenty of native mountain soil, sprayed with water frequently, and fertilized with dilute cake fertilizer water mixed with a small amount of ferrous sulfate. In summer, it should be placed in a shaded spot or under tree shade; it is even better if the pot is placed on wet sand.

(III) Potting Process

Pot selection: Boxwood is suitable for purple clay pottery pots or glazed pottery pots. Pot shapes are mostly medium-deep rectangular or elliptical; for cascade style, a deep cylindrical pot is suitable. Pot colors are best in purple or light yellow to highlight the emerald green branches and foliage.

Soil: Boxwood prefers fertile, loose loam and adapts to slightly acidic or slightly alkaline soil; it can also grow in calcareous soil. For potting, use weathered garden soil or leaf mold mixed with an appropriate amount of rice husk ash.

Planting: Generally carried out before spring budding. When planting, properly prune overly long and dense roots, and do not let the root system become coiled in the pot.

(IV) Shaping Techniques

Processing: Old boxwood stumps collected from the wild are generally cultivated for 1-2 years before processing begins, while seedlings cultivated from a young age must wait 3-4 years before processing can begin. Styling is mainly by wiring, and coarse wiring with fine pruning can also be used. Boxwood branches are hard and the bark is thin, so metal wire should not be used for wiring; palm fiber is best. Wiring is mostly done in spring, while pruning can be done at any time.

Tree forms: Boxwood is suitable for slanting-trunk style, curved-trunk style, and cascade style, etc. In the traditional forms of "Yangzhou-style" bonsai, the branches and foliage of boxwood are all made into "cloud pads" using the "fine wiring and fine pruning method," while in "Suzhou-style" bonsai, the "coarse wiring and fine pruning method" is used to create a "steamed bun" shape, each with its own characteristics. Boxwood has strong sprouting ability and tolerates pruning very well, and can also be processed by pruning into a natural large-tree form. If a boxwood bonsai is paired with ornamental stones, it becomes "boxwood with stone," making the old-looking, small tree grow beside the stone, giving it a more natural and marvelous appearance.