How to grow a boxwood (Buxus sinica var. parvifolia) bonsai? A detailed guide to care methods

Adequate sunlight and water. For placing a boxwood bonsai, it is best to choose a spot where "it gets sun in the morning, is fairly shady in the afternoon, has good air circulation, and relies on natural dew and rain." If kept indoors for viewing, it is best to let it go back out to sun and rain after ten days to half a month. The pot of a boxwood bonsai should be kept moist at all times, because its root absorption, leaf photosynthesis and entire growth process all require a large amount of water, though of course the amount needed also changes with the seasons and climate. The boxwood has gone from the banks of rivers and streams to growing in a small pot in the garden, and the biggest change in environment is that the humidity is lower, which we must make up for with timely and appropriate watering through our care. So watering must take the climate into account, must be done with skill, and must ensure quality. When the temperature is above 20°C and the pot is short of water, water in three steps: step one, flush without disturbing the soil (to meet the water needs in the pot); step two, wet the branches and leaves thoroughly (water from multiple angles); step three, mist. In hot weather or when the temperature is above 20°C and the pot is not short of water, just do steps two and three. When the temperature is below 20°C and above 10°C and the pot is not short of water, in winter in the morning sunlight, water once a day following only step three. After "White Dew" in autumn, once the dew has dried, mist following step three. On frosty days do not water in the morning or evening; before a cold wave in the "sanjiu" period (the coldest days), do not water to prevent freezing the soil and freezing the branches and leaves, and likewise keep the drainage and aeration in the pot good.

Light fertilizer, applied frequently. For boxwood, fertilizer should mainly be base fertilizer, mainly natural fertilizer, and mainly human and livestock manure. Apply chicken and duck manure and high-efficiency fertilizers with caution, and remember never to apply unrotted fertilizer or over-fertilize; achieve light fertilizer applied frequently. Apply a seasonal fertilizer before the seasons change, such as a sprouting fertilizer in early spring, a leaf-strengthening fertilizer in summer, a heat-resistance fertilizer in hot weather, and an insulation fertilizer in winter; after each pruning apply a little compensation fertilizer, in the rainy season and hot weather when the pot is over-watered apply a little supplementary fertilizer, and for poor growth apply fertilizer as appropriate.

Shaping mainly by pruning. Boxwood wood is hard and brittle, and the branches have thin bark that is easily damaged, so it is not very malleable. Therefore, first pay attention to selecting the stock, then suit measures to the tree and guide it according to its tendencies; shaping must be mainly by pruning. You can also appropriately use rope to bind and pull; branches that need a large change in position should be moved into place over several steps, that is, you must neither be too demanding nor rush for success, otherwise you will get the opposite of what you want. Do not use rusty iron wire to twist branches: first, to prevent damaging the bark, and second, to prevent killing the branches.

The trunk of a boxwood bonsai grows very slowly and is extremely rugged and vigorous, but the young branches grow quickly, and the density of the leaves will inevitably be stretched out, making it look soft and loose. Only by using "pinching" to control it can its ornamental value be ensured. That is, before the branch has become woody, keep one pair, or at most two pairs, of young leaves and remove or cut off the rest; under appropriate conditions of water, fertilizer and so on, in ten days to half a month it will send out two young shoots. Repeating this cycle over and over, its branches appear short and thick, and the leaves can multiply by powers of 2, continuously raising its ornamental value. Also, promptly remove the flower buds. Boxwood begins to have flower buds before summer and autumn, and blooms in spring; the flowers and fruit need 70%-80% of the nutrition of the whole tree, which will inevitably affect its normal growth and beauty, and we mainly grow it for its foliage. So from the moment buds are seen, they must be removed.

Repotting requires shortening most roots. Boxwood has fine fleshy roots, and its water and nutrient absorption depends mainly on the absorbing function of the root tips, with the length of the root arms being secondary. If the roots are left long, they cannot spread out in the pot. Bending and kneading them is very harmful. Moreover, in order to absorb nutrients, the root tips will naturally extend forward and contact the new soil. If the roots are left long, before long the root tips will hit the wall; although root tips will turn, it takes effort and time and affects growth. In particular, the pot wall and pot bottom will quickly be filled with a tangle of roots, forming a soil-less "root plate," requiring repotting again. This creates a vicious cycle. When repotting with soil (do not carry too much soil), cut off the long roots exposed above the soil surface. The best seasons for repotting are, first, early spring (after the roots are established, it can sprout). Second, the hot season when growth is vigorous (after repotting, place it in a cool, shady spot for seven or eight days, and it will recover its vigor).

Preventing and controlling tortricid moth larvae. Tortricid moth larvae like best to suck the leaf sap of boxwood. After hatching, the leaf-roller caterpillar spins silk and can roll the surrounding leaves into a ball, hiding in the middle to suck the leaf sap; in two or three days it will have sucked all the sap from the rolled leaves, leaving a white network of leaf veins, and then it moves on to do harm elsewhere. If not caught and killed in time, in five or six days it will destroy all the leaves. This not only ruins the beauty, but trees in poor condition may die because of it. Leaf-roller caterpillars can be killed by ordinary pesticides that work by "sucking-kill" or "contact-kill"; the key is to discover and wipe them out in time. It is worth noting that tortricid moth eggs, in hot weather, especially when the temperature is above 30°C, can hatch into harmful young larvae in just three or four days, the fastest generation turnover. So when the temperature is high, it is best to catch and kill them once a week.