Detailed Explanation of the Production Methods and Shaping and Pruning Techniques for Chinese Hackberry Bonsai

Chinese hackberry is a deciduous tree of the order Rosales, distributed in Henan, Shandong, the middle and lower reaches of the Yangtze River and the provinces and regions to the south, as well as Taiwan, China; it is also found in Vietnam and Laos. This tree is often cultivated as bonsai. Next, let us learn about it in detail.

1. Botanical knowledge

Belongs to the family Ulmaceae, genus Celtis. Deciduous tree, bark rough, grayish-black, not cracking. Leaves simple, alternate, ovate-oblong or broadly ovate, base obliquely unequal, with 3 main veins, margin serrate above the middle, surface dark green, underside pale green. Flowers polygamous-monoecious, male flowers borne on the lower part of new shoots, bisexual flowers solitary or in clusters of 2 to 3 in the leaf axils of the upper part of new shoots, flowers small, pale green. Drupe nearly spherical, orange-yellow or orange-red when ripe, usually solitary or in pairs, fruit stalk nearly as long as the petiole. Flowering period April to May, fruit ripening period September to October.

Chinese hackberry is produced in the Huai River basin, south of the Qinling Mountains, and south to Guangdong, Guangxi and other provinces and regions; it is a subtropical tree species. It is mostly scattered in plains and low mountain areas.

It prefers light, is suited to warm and humid climates, and is suited to fertile, flat ground. It is not demanding about soil, has a certain tolerance for drought, and also tolerates waterlogging and poor, thin soil, with relatively strong adaptability.

2. Material collection and cultivation measures

Artificial cultivation: Chinese hackberry is usually propagated by sowing. The seeds mature from September to October, and the fruit turns reddish-brown; it should be collected promptly, spread out in the shade to dry, with debris removed, then mixed with sandy soil and stored. Sow in March of the following spring. Before sowing, the seeds must be treated by cracking the seed shell with a wooden stick, or scratching the outer seed coat with sand, before sowing; this helps the seeds germinate. The seedbed soil should preferably be loose, fertile, well-drained sandy loam. After sowing, cover with a layer of fine soil about 2 cm thick, then cover with rice straw, and water thoroughly once; germination can begin in about 10 days. After the seedlings emerge, remove the straw promptly. During the seedling stage, good maintenance and management work must be done, paying attention to loosening the soil, weeding, topdressing, and appropriate thinning. One-year-old seedlings can reach 30 to 40 cm in height. For young saplings cultivated for Chinese hackberry bonsai, attention should be paid to pruning and shaping, suppressing the leader and promoting side growth, controlling the height growth of the sapling, and promoting thickening of the trunk and growth of side branches, so as to facilitate potting and shaping.

Collection from the wild: Chinese hackberry is commonly found growing wild beside hills, low mountains and stream valleys in the Yangtze River basin and areas to its south. Old stump sprouts of ancient and unusual form that have been cut back for many years can be collected and grown on for root and trunk development. After pruning, root development is promoted and new branches sprout; then they are shaped and cultivated. After 1 to 2 years, they are potted and processed, and a vigorous, ancient-looking Chinese hackberry bonsai can be produced in a relatively short period.

3. Potting process

Pot selection: Chinese hackberry bonsai is noted for its antique elegance, so it is suitable to use a purple clay pottery pot or a glazed pottery pot, with pot shapes preferably rectangular, square or oval, depending on the tree form. Because Chinese hackberry has dense foliage, deep green leaf color, and grayish-brown, rough bark, pot colors of light yellow or ochre-brown are best, serving as a contrast and foil.

Soil use: Chinese hackberry is not choosy about soil and has strong adaptability, but grows better in fertile, loose, well-drained sandy loam. For bonsai cultivation, a growing medium generally made by mixing garden soil with sandy soil or rice husk ash is used.

Planting: It is suitable to carry out after autumn or before spring bud break. When planting, the root system should be properly pruned and arranged, cutting off overly long main roots and retaining more lateral roots and fibrous roots, then mounding with loose fertile soil; at the same time, the branches and leaves should also be properly thinned. If planting in a medium-shallow pot, the roots must be fixed to the bottom of the pot with wire to prevent lodging.

4. Shaping techniques

Processing: Chinese hackberry shaping mostly uses the method of coarse wiring and fine pruning, while the Lingnan school's large tree form processing completely adopts the pruning method, imitating Lingnan painting techniques, emphasizing pruning skills, accumulating branches and truncating the trunk, and valuing the overall compositional effect. Finished shaped stump bonsai can maintain a beautiful form whether in the lush foliage season or in the winter leafless state.

Tree forms: Chinese hackberry bonsai is suitable for being made into forms such as formal upright, slanting, curved trunk, lying trunk, or root-over-rock. The branches and leaves can be wired into pads or pruned into steamed-bun-shaped round pads, and can also be processed into a natural tree form.

Material Selection and Shaping Production Procedures for Water-and-Land Bonsai

Lingnan Bonsai Cultivation and Management Techniques

        (1) Tools
① Scissors. Scissors used for pot trees include spring scissors, long-handled scissors, and small scissors, etc. Spring scissors are mainly used for pruning branches and roots, long scissors are used for trimming fine branches and leaves, and small scissors are used for pruning and wiring. All kinds of scissors must be sharp and sturdy.

② Hammers. There are wooden hammers, small iron hammers, etc., mainly used for processing tree stumps.

③ Crescent chisel. Mainly used for working on saw cuts and scars on the trunk and for carving and hollowing the tree body to give it a rugged, withered appearance.

④ Saw. There are ordinary wood-cutting hand saws and hacksaws; the most convenient to use is the cockatoo saw. Mainly used for sawing off thick trunks and thick roots.

⑤ Pliers. Ordinary electrician's pliers. Mainly used for tying and binding wire.

⑥ Knife. Includes grafting knives and ordinary small knives. Mainly used for trimming and cutting branches and trunks during grafting.

⑦ Small garden trowel. Mainly used for shoveling soil, mixing soil, and blending mud when potting, as well as for lifting seedlings, transplanting and digging holes.

⑧ Bamboo stick. Used for loosening the soil around the pot when repotting and removing excess soil from the tree roots; used for tamping down the root soil when planting potted trees; and used for digging out planting holes when taking cuttings of branches and trunks, to prevent damage to the base of the cuttings.

⑨ Watering can. There are large, medium and small three types of swivel-nozzle watering cans; sturdy and lightweight ones are preferable. Mainly used for watering; with the nozzle removed it can also be used for applying liquid fertilizer.

⑩ Sprayer. Used for spraying and moistening the stumps of newly planted tree species, spraying the leaves of potted trees, and spraying liquid pesticide.

Fertilizing vessels. Includes water buckets, small ladles, watering cans, etc.

Sieve. There are two types, bamboo-made and metal-made, divided by mesh size into large, medium and small three kinds. Metal ones are the most durable.

Boxes. Use various empty wooden boxes to cultivate seedlings, hold potting soil and various small tools and sundries.

Miscellaneous items. Rags for cleaning vessels, brushes for brushing branches and trunks, iron wire, steel wire, hemp twine and plastic tape for tying branches of various thicknesses, etc.

Chemicals. Trichlorfon, dichlorvos, dimethoate (Rogor), phosmet and other chemicals for controlling insect pests.


(2) Temperature

Temperature is one of the main conditions for plant survival. The growth and development of plants and all their life activities require a certain amount of heat; without suitable temperature conditions, no plant could survive. Plants generally can grow within the range of 4 to 36 degrees Celsius, but their temperature requirements are not all the same. Some plants prefer low temperatures, some prefer moderate temperatures, and some prefer high temperatures. Within a certain range, the higher the temperature, the more vigorous the photosynthesis; between 10 and 35 degrees Celsius, for every increase of 10 degrees Celsius, respiration increases threefold, and appropriately lowering the temperature can delay plant growth. However, above or below a certain temperature, plants cannot survive. During hot seasons, plants transpire heavily; if the water supply is insufficient, plant cells will lose a large amount of water and wilt. As air temperature rises, the soil surface temperature rises accordingly, directly hindering root growth, which is also one of the causes of plant wilting. If the temperature exceeds 50 degrees Celsius, plants will lose their vitality because the proteins in their bodies coagulate. When the temperature drops to freezing point or below, the tissues within the plant body will also freeze; at this time plant cells lose water, proteins precipitate, and the plant dies because metabolism stops. This phenomenon can sometimes be seen from the exterior of frozen plants, such as leaves becoming hard, bark frost-cracking, and the bark separating from the woody part. In the Guangzhou area, the average annual temperature is about 22 degrees Celsius, so potted trees in the Lingnan region are suited to growing between 20 and 35 degrees Celsius.


(3) Light

Light is a necessary condition for photosynthesis in all green plants and is also the source of energy for green plants. Within a certain range, the more hours of light, the greater the photosynthetic output of the plant, and the more organic matter and energy accumulated in its body. This has a direct influence on the germination and growth of plants, as well as on the transition from the vegetative phase to the flowering and fruiting phase.

The intensity of light can also cause a series of complex changes in other ecological factors, causing changes in the temperature and humidity of the atmosphere and soil, and thus indirectly affecting many physiological processes of plants. For example, light increases the permeability of protoplasm in plants and has a direct or indirect influence on plant transpiration.

However, different regions and different tree species have different requirements for light. Some tree species do not need strong sunlight, while others must grow in an environment with abundant sunlight.

Based on the adaptability of plants to the length of light exposure, plants can be divided into short-day plants and long-day plants. Plants native to temperate or cold zones are mostly long-day plants, while plants native to tropical and subtropical regions are mostly short-day plants. Long-day plants need 12 to 18 hours or more of light per day to flower; if the light is short and the night is long, they will only grow lush foliage and cannot flower. Guangdong is located in the hot, rainy tropical and subtropical zone, where the differences between the four seasons are not very obvious, winter is shorter and warmer, and plants can grow almost all year round. Therefore, for cultivating Lingnan tree stumps for foliage, flowers and fruit, as long as there are about 8 to 10 hours of light per day, the plants can have luxuriant branches and leaves and can flower and bear fruit. In this way, we must, according to the type of potted tree, adopt different lighting methods and light-exposure times, and regularly move the potted trees to promote their growth.


(4) Air and Wind

Oxygen and carbon dioxide in the air are of great significance in plant life; they are indispensable components for plant photosynthesis and respiration and are necessary conditions for plant life. However, in large cities and industrial areas, toxic gases such as chlorine, hydrogen chloride, sulfur dioxide and nitrogen dioxide emitted from the smokestacks of various factories have a certain effect on the growth of potted trees. In addition, dust falling on leaves will clog the stomata and hinder gas exchange in the leaves, which is unfavorable to plant respiration; moreover, when dust covers the leaf surface, it also reduces the intensity of plant photosynthesis. The main protective measure is to combine morning and evening watering with rinsing and spraying the leaf surface.

The influence of wind on plants has both favorable and unfavorable aspects. Wind can often accelerate the transpiration of potted trees. If the wind speed is too great, not only does water evaporate too quickly, but it can also snap branches or blow over potted trees, causing losses. Therefore, when the wind is too strong, the potted trees should be moved. If they can be placed in a place with circulating air, it will benefit the plants; this not only regulates the air, lowers the temperature, helps plants transpire naturally, but also prevents pests and diseases.


(5) Soil

The relationship between soil and plants is both close and complex. Except for a few parasitic plants and floating aquatic plants, the vast majority of plants grow in soil. Soil is not only the place that anchors plants, but also the supplier of water and inorganic salts necessary for plant life. Soil air is also an indispensable factor for plant growth and development; it has a direct or indirect influence on the respiration of plant roots, the physiological functions of the whole plant, the types and quantities of soil microorganisms, and the nutritional status of plants. The water content and temperature in the soil also have a great influence on plant life.

Soil is a complex whole; it contains mineral soil particles, organic matter, inorganic nutrients and various different substances, as well as soil microorganisms and the products of their activity - humus - along with water and air, etc. All these components in the soil and their interrelationships affect the properties and fertility of the soil, thereby affecting plant life and its geographical distribution.

The soil for planting potted trees must have good air permeability and drainage. We know that plant roots, in addition to absorbing water and nutrients from the soil, also need oxygen in the soil, so pot soil is suitable for use in combination with several granular soils that have good air permeability and drainage. In addition, the soil should also have water retention capacity. So-called water retention means that the gaps between soil particles can fully retain water. Soil that possesses air permeability, drainage and water retention is an ideal granular soil.

For potting soil, in addition to having air permeability, drainage and water retention, suitable soil should also be selected and blended according to different tree species. Because different tree species have different requirements for soil, some like fertile soil, some like loose mountain soil, some like acidic soil, and some like alkaline soil, so the soil quality for potted trees must be carefully selected and blended.

There are many types of soil used for potted trees, and the vast majority of soils are suitable for use. However, some soils that are too heavy in clay, because their gaps are small, drain and breathe poorly, and are not suitable for use alone. Several commonly used pot soils and their properties are listed below for reference.

① Pond soil. Pond soil is mostly dug out from ponds that have been drained after growing watercress, water spinach, or fish. The mud dug out is placed on the bank, spread flat and dried in the sun, made into mud bricks of about 15×20 cm, and after drying thoroughly, broken up for use. Pond soil is relatively fertile and suitable for the vast majority of potted trees. Such mud bricks are sold in flower and plant shops.

② Mountain soil. Mountain soil is the natural leaf mold of mountain forest areas. After long-term weathering, mountain soil is dark brown, fine-grained and loose, contains organic matter, drains and breathes well, and is most suitable for cultivating pine and cypress tree species.

③ Leaf mold. Generally, tree leaves and grasses are buried in soil, and after rotting they become leaf mold, which contains nitrogen fertilizer; the soil is loose and fertile, and should be mixed with sand and field soil when used.

④ Red mud. Red mud is red or dark red; the amount of sandy material in the original soil depends on the degree of stickiness of the red mud. But regardless of the degree of stickiness, it can be used for cultivating potted trees, though it must be mixed with sand, mountain soil or leaf mold before use.

⑤ Sand. There are three kinds of sand: sea sand, river sand and mountain sand. Sea sand, because it contains salt, is not suitable for cultivating plants. River sand and mountain sand can be used together with sticky soil, or spread beneath other soil as a bottom layer to facilitate drainage; they can also be placed in a sand box for use with cuttings, but sand cannot be used alone to cultivate potted trees.

⑥ Potting soil. In cities it is generally rather difficult to obtain soil, and buying flower soil from flower shops costs more; to save expenses, you can make potting soil yourself. The method of making it is simple: you can use the old pot soil removed during repotting, mix it with chicken manure, crushed bones, garbage, plant ash and thoroughly burned coal cinder, dry it in the sun, then add human excrement and urine, and after repeated turning, mixing and drying, store it in a jar or box for use at any time. This kind of potting soil is not only loose, with good drainage and air permeability, but also has notable fertilizer effect.

⑦ Clay. Clay has a large water-retention capacity; the size of its water-retention capacity depends on the number of extremely small soil particles per unit of soil. Small soil particles can retain soil moisture better than large ones. However, clay has poor water permeability and air permeability, and is not suitable for use alone; it is best used after mixing with sand and applying organic fertilizer.

⑧ Sandy soil. Sandy soil has relatively large soil particles and better aeration and water permeability, so water and fertilizer in sandy soil are easily lost, and the upper layer of the soil dries out easily; therefore sandy soil must be improved, changing its structure and fertility, to benefit plant growth.

(6) Water

Water is an indispensable factor for plant growth. Every plant body contains water; all metabolic processes of plants can proceed normally only when water is present; at the same time, water is also a necessary raw material for photosynthesis in green plants. Therefore water determines the life activities of plants. The water needed for the life of most plants is mainly absorbed by the roots. Potted plants grow in pots of limited capacity and mainly rely on watering to maintain the moisture in the pot soil. Therefore watering has become a very important management task.

For watering, you must first understand the water quality. There are many sources of water - rainwater, river water, well water, pond water and tap water can all be used, but water containing salt and turbid water should not be used. Second, pay attention to water temperature. In order to reduce the stimulation of water on potted trees, you must pay attention to controlling the water temperature. In summer the temperature is relatively high; if you water potted trees with water whose temperature is too low, the absorptive capacity of the potted tree's roots will be weakened, and the upper branches and leaves will shrivel due to insufficient water supply. Therefore, at the maintenance site it is best to first store water in a water tank or reservoir and let the sun shine on it, in order to raise the water temperature accordingly. In cold regions, in winter the water should be stored indoors for one or two days, and used only after the water temperature has risen to a point where it does not differ too much from the air temperature; this will not damage the roots of the potted trees. Third, you must grasp the amount of water. In long-term practice the author has made observations and comparisons: the same kind of plant grown in soil with sufficient water and in dry soil shows changes in both its form and the size of its branches and leaves. The leaves of plants growing in moist soil are usually relatively large, while the leaves of plants growing in dry soil are generally relatively small. As far as tree stump bonsai is concerned, if the pot soil is too dry, it will cause the fine roots to dry up, and afterward even watering cannot restore absorption; the root system then begins to rot, the leaves also turn yellow and withered, and slowly the whole plant dies. If the pot soil is too wet and contains too much water, there will be little air, the respiration of the root system will be blocked, causing suffocation and making the root system rot and die. Based on the above, for different plant species, according to the age of the tree, the strength of growth, and different seasons, temperatures, soil qualities, and the texture and size of the pot, the number of waterings and the amount of water should differ.

No matter what the season, watering potted trees should achieve “water thoroughly when dry”; never water with “half water”. Half water means that only the upper layer of the pot soil absorbs it and it does not seep down to the lower layer of the soil, so the top is moist while the interior of the soil is dry; the root system cannot obtain water and will die. Therefore, when watering, special attention must be paid to watering thoroughly.

(1) Principles of Watering

① Water according to the season. After the Beginning of Spring, the temperature gradually warms up, potted trees enter the season of vigorous growth, and the amount of watering should increase accordingly. In summer the weather is hot, potted trees grow rapidly, water evaporation is greater, the pot soil dries easily, and the amount of watering should also increase accordingly. After the Beginning of Autumn the weather turns cooler, potted trees gradually slow their growth or basically stop growing, consume little water, and should be watered less or every other day. In winter, if watering is needed, it must be done during the warm part of the day, and the amount of watering should be such that by dusk the pot soil is slightly dry.

② Water according to the weather. When the temperature is high or the climate is dry, because water evaporates quickly, water in time. When the temperature is low or the weather is cloudy and rainy, water evaporates more slowly and plants need less water, so you can water less or not at all.

③ Water according to the plant's growth condition and habits. When tree stumps are sprouting, water should not be too much, as this can control the growth of young buds; too much water may cause the young buds to grow leggy or rot. When potted trees enter the stage of vigorous growth, they should be watered more. When flowering, however, care should be taken to reduce water to prevent flower drop. Plants have different habits and therefore different water requirements. A simple way to distinguish them is to decide based on the size of the plant's leaves: plants with fine, small leaves do not like water, because small leaves evaporate less water and therefore need less water. Those with large leaves are mostly water-loving, so they need more water. Grasp these characteristics when watering, and you can ensure plant growth.

④ Water according to the soil quality. Sandy soil drains well; when plants are planted in this kind of soil, they need more water, so watering should be frequent. Clay soil and leaf mold can store relatively more water, so appropriate watering is enough.

⑤ Water according to the texture, size and depth of the pot. When watering, you must decide according to the texture, size and depth of the pot. Earthen pots are breathable and water-permeable, and the pot soil dries easily; glazed pots, stone pots and ceramic pots are not very breathable, and the pot soil dries with more difficulty; porcelain pots are not breathable and not water-permeable, and the pot soil does not dry easily. Because pots differ in size and depth, the degree of dryness and wetness of the soil in the pot also differs; generally, the pot soil in small pots dries faster than in large pots, and the pot soil in shallow pots dries faster than in deep pots. When watering, distinctions should be made according to the above situations.

⑥ Do not cut off the water. There is little soil in the pot, and the water it stores is limited; exposed to wind and sun, the pot soil dries very easily. In hot seasons, of course you must water frequently; and on crisp autumn days, you must not neglect watering either. Even for potted trees that shed their leaves and go dormant in winter, you must not let the pot soil become too dry, but should maintain relative humidity. Especially for water-loving potted trees, water must never be cut off at any time.

⑦ Control water. In order to maintain the beautiful posture of potted trees that have already been trained and properly pruned, when they are displayed for viewing (especially indoors), by all means do not water too frequently; it is better to err on the dry side than to be too wet, so as to avoid leggy branches and leaves and difficulty in root respiration, which would affect the growth and beauty of the potted trees.

(2) Methods of Watering

① Spraying water. For newly planted tree stumps or potted trees after soil replacement, the roots have more or less suffered some damage and find it relatively difficult to absorb water, so a fine-hole watering can may be used to spray water; the water stream sprayed out this way is small and even, and will not disturb the pot soil or affect water absorption by the roots.

The first watering should be sufficient to soak through to the bottom of the pot; afterward, the trunk, branches and leaves should also be sprayed frequently, and the pot soil kept moist. As for large areas, a rubber hose may be used for spraying according to actual conditions.

② Sprinkling water. Trees such as rhododendrons, pines and cypresses that naturally grow in high mountain cloud and mist are accustomed to absorbing moisture in the forest. Once transplanted into pots and having changed environment, their growth will be affected to a certain degree. In order to adapt to their growth habits, water must often be applied to the leaves. This not only washes away the dust accumulated on the branches and leaves and keeps the potted trees beautifully colored, but also clears the stomata on the leaf surface and promotes plant metabolism.

But for some potted trees, if their leaves are watered too much, it instead causes their branches and leaves to grow leggy; for example, orange jasmine, pomegranate, elm, etc. are not suitable for sprinkling water on the leaves.

③ Soaking water. For potted trees planted in shallow pots and miniature bonsai, the pot soil is shallow and little; after being exposed to the scorching sun, the pot soil hardens, turns white and shrinks, developing cracks, and some becomes blocky and separates from the pot. When watering at this time, the water often quickly flows from around the pot to the bottom and is lost through the drainage hole. In this situation, the potted tree should be placed in a larger basin full of water and allowed to absorb water thoroughly until no more bubbles rise to the surface, then it can be lifted out.


(7) Fertilizing

The pots of tree stump bonsai are small in volume, and the nutrients in the pot soil are limited; sufficient nutrients must be provided in time for them to grow well and develop normally. Potted trees continuously absorb various nutrients during growth, so they must be fertilized regularly; but too much fertilizer at one time is not advisable, as excessive fertilizer makes branches and leaves grow leggy, affecting the beauty of the potted tree's posture and hindering viewing; while a lack of fertilizer means insufficient nutrients, causing the tree's branches to become thin and weak, the leaf color to turn yellow, development to be inhibited, and the tree to become vulnerable to pests and diseases, resulting in the death of the potted tree. Therefore, you must have a good grasp of basic knowledge such as the types of fertilizer, their functions, methods of preparation, and the principles and methods of fertilization. In short, they must be used flexibly according to the time, the place, the fertilizer and the tree species, in order to achieve the purpose of fertilizing.

(1) Types and Functions of Fertilizers

There are many kinds of fertilizers, but those used for tree stump bonsai are none other than the two major categories: inorganic fertilizers and organic fertilizers.

Inorganic fertilizers refer to chemical fertilizers, also called mineral fertilizers; they are manufactured by the chemical industry, such as ammonium sulfate, ammonium nitrate, ammonium chloride, urea, etc. as nitrogen fertilizers; superphosphate, phosphate rock powder, etc. as phosphorus fertilizers; and potassium sulfate, potassium chloride, etc. as potassium fertilizers. After the nutrients of chemical fertilizers are absorbed by plants, acid radicals or salt bases will remain. After excessive use of chemical fertilizers, the limited pot soil will become acidic or alkaline, hindering plant growth. Therefore, tree stump bonsai should avoid the application of chemical fertilizers as much as possible.

Organic fertilizers are also called farmyard fertilizers. Commonly used ones include human excrement and urine, poultry manure, bone meal, as well as soybean cake, rapeseed cake, various green manures and plant ash, etc. These fertilizers contain large amounts of organic matter and respectively contain different proportions of the elements nitrogen, phosphorus and potassium. Organic fertilizers play a major role in improving soil properties and raising soil fertility; organic fertilizers have a mild fertilizer effect and cause no side effects after application, and are indispensable nutrients for plant growth.

The functions of various fertilizers are different. Nitrogen fertilizer has the effect of promoting luxuriant branches and leaves; phosphorus fertilizer has the effect of promoting seed germination, growth, and the formation of flowers and fruits; potassium fertilizer has the effect of promoting sturdy, tough stems and branches that are not prone to lodging, as well as well-developed roots and absorption, thereby enhancing the potted tree's ability to resist cold, drought, pests and diseases.

After mastering the types and functions of fertilizers, they can be applied according to different needs such as foliage viewing, flower viewing and fruit viewing.

(2) Methods of Preparing Commonly Used Fertilizers

① Composting human and livestock excrement and urine. Human and livestock excrement and urine have wide sources and a relatively notable fertilizer effect, and are commonly used by people. However, fresh, thick human and livestock excrement and urine that has not been stored and not fully decomposed should not be used, because plants cannot easily absorb it and it will harm the plant root system. Therefore, human and livestock excrement and urine must be stored in a jar, covered and sealed at the mouth, and kept in a cool place; only after 10 days to one month of decomposition can it be applied. When applying, it should be diluted with several times or several dozen times clear water; if the manure water gets on the leaves, rinse immediately with clear water to avoid burning the leaves.

② Soaking crushed soybean cake, peanut cake, rapeseed cake, and crushed animal bones. Put the above crushed fertilizers into a jar, add about ten times water to soak, cover and seal the jar mouth to prevent rainwater from entering, and store for about twenty to thirty days before use. When applying, dilute with clear water twenty to thirty times.

③ Treatment of bone meal. After animal bones are steamed, the fat is removed, and then after drying and grinding they become bone meal. The phosphorus in bone meal exists in the form of the sparingly soluble tricalcium phosphate, and is suitable as a base fertilizer, applicable to acidic soil.

(3) Fertilization Methods

① Base fertilizer. Fertilizer applied to the soil before sowing, transplanting, planting out or changing soil is called base fertilizer. The main function of base fertilizer is to supply the nutrients needed for the entire growth and development of the crop, and it also has the effect of comprehensively improving soil properties. Base fertilizer is mostly organic fertilizer; the method of application is to place granular, powdered peanut cake, soybean cake, rapeseed cake, cottonseed cake fertilizer or bone meal, etc. as a layer at the bottom of the pot or around the sides of the pot, letting it slowly decompose and be absorbed. But be careful not to apply excessively, otherwise it will burn the root system and seedlings. Base fertilizer alone is far from sufficient to meet the long-term growth needs of potted trees; this would cause the potted trees to develop incompletely and gradually weaken. Therefore, base fertilizer and top dressing must be combined organically.

② Top dressing. Fertilizer applied during the plant's growth period is called top dressing. Top dressing mostly uses thin liquid fertilizer. In applying top dressing, the principle of frequent and light application should be grasped. Under normal circumstances, potted trees are fertilized once every seven days, and after autumn this can be extended to about once every twenty days. When applying, distinctions should be made according to tree species and their different growth stages: after budding and rooting, nitrogen fertilizer should be the main top dressing to promote the development and luxuriance of branches and leaves; before flowering or during the fruiting period, phosphorus and potassium fertilizers should be the main top dressing, while also applying an appropriate amount of nitrogen fertilizer; after flowering and fruiting, the potted tree's vigor must be quickly restored, so top dressing must be applied about once every fifteen days until it can be stopped only after autumn.

(4) Principles of Fertilization

① Fertilize according to the needs of the potted tree's growth period. Fertilization must be based on the growth and developmental needs of the potted tree at each different stage. For newly planted potted trees, those just potted, or those just repotted with changed soil, the root system has suffered a certain degree of damage; for safety's sake, do not fertilize for the time being, and afterward apply top dressing as appropriate according to the growth condition of the potted tree. During the vegetative growth period of the potted tree, nitrogen fertilizer should be applied to make branches and leaves luxuriant; to promote seed germination, the growth of young roots and young buds, and fresh flower and leaf color and plump fruit, phosphorus fertilizer may be applied; to strengthen the root system, trunk, and branches, potassium fertilizer is suitable. Fertilizer may also be applied when the potted tree's leaf color becomes pale or yellow or the plant is thin and weak.

② Fertilize according to the season and weather. Fertilization should be based on the season. Spring and summer are the peak growth seasons for potted trees, so more fertilizer must be applied. After autumn begins, potted trees grow slowly, so less fertilizer should be applied. In winter, potted trees enter dormancy, so fertilization may be paused or a little potassium fertilizer applied.

Fertilization should also take the weather into account. Fertilization is not suitable on rainy days or around midday in summer when temperatures are high. Because fertilizing on rainy days makes the fertilizer components easily lost; fertilizing in high-temperature weather easily damages the potted tree's root system. Therefore it is best to fertilize on cloudy days or in the evening, after the pot soil has dried, for a better effect.

(5) Points to Note

① Weed and loosen the soil before fertilizing. During growth, potted trees also grow many weeds, which compete with the potted trees for nutrients. The surface of the pot soil also becomes compacted. Therefore, before fertilizing, first remove the weeds, then loosen the soil with a bamboo stick; this not only helps fertilizer water seep into the soil and helps microorganisms reproduce, but also promotes the accelerated decomposition of organic fertilizers in the soil, providing plants with multiple elements and enabling them to grow well.

② Water after fertilizing. After fertilizing potted trees, water more; otherwise, with much fertilizer and little water, the fertilizer after fermentation produces high temperatures and the root system will be burned. In severe cases it can lead to death. Therefore, after fertilizing potted trees, clear water must be applied the next morning, commonly called “return water”; this not only favors the absorption of fertilizer components but also avoids fertilizer damage.

③ Grasp the site of fertilization. No matter which liquid fertilizer is applied, by all means do not apply it on the young buds and new leaves of the potted tree, to prevent burning.

(8) Pruning

During the cultivation process of tree stump bonsai and after they have been trained into shape and potted, necessary pruning and shaping should be carried out. If not pruned for a long time and allowed to grow freely, even potted trees that were originally shaped will produce a tangle of miscellaneous branches, chaotic and disordered, to the point that the tree stump bonsai can no longer develop in a balanced way, affecting the beautiful tree form; moreover, poor ventilation and light will cause some branches and leaves to wither and drop and lead to pests and diseases. Therefore, frequent pruning of tree stump bonsai is, on the one hand, to maintain the basic form of the potted tree and even growth in all parts, and on the other hand, to cut away overly dense branches and leaves that obstruct ventilation and light, regulate tree vigor, make the tree stump grow vigorously, and renew old branches. Only in this way can the goals of being beneficial for viewing and also preventing pest and disease damage and enabling healthy growth of the potted tree be achieved.

In terms of pruning methods, leaves should first be thinned. You must see the whole tree clearly before starting; once you cut wrongly, you will destroy the tree form. At the same time, different methods such as branch pruning, pinching, bud removal and leaf removal should be used according to differences in tree species, growth vigor and season.

① Branch pruning. After potted trees have taken shape, they are still continuously growing; especially in spring and summer, the branch tips grow rapidly and densely, and the tree form is not easy to fix. In order to control the potted tree's original form and highlight the main trunk and main branches, branch pruning must be carried out. Branch pruning can be done during the dormant period and the growth period. But the number of prunings should vary according to the different habits of tree species and different seasons. For foliage-viewing tree stump bonsai, such as pines and cypresses, pruning can be carried out three times each year in March, June and August respectively; for strong-sprouting elm, Chinese bird plum, Fujian tea, orange jasmine, skyflower, etc., generally three to five prunings per year, and it can be done in all three seasons of spring, summer and autumn.

Generally speaking, branch pruning should follow the following principles: First, potted trees with strong, vigorous growth can be pruned in all four seasons. In order to ensure the potted tree's vegetative growth, for potted trees with weak growth, do not prune much or do not prune, and prune only after they become vigorous. Second, in summer's high temperatures, pruning may be appropriately reduced or temporarily suspended. Of course, dead branches and pest- and disease-infested branches of potted trees must be cut off and burned at any time, so as not to affect the tree's growth. Third, leggy branches, radiating branches, crossing branches, overlapping branches, straight branches, etc. should be cut off first. Fourth, the thinning or retention of branches should be determined according to the characteristics, layout and requirements of the potted tree; branches, spurs and leaves that hinder viewing should be thinned and pruned so that they interweave and set each other off, with an appropriate balance of density and sparseness.

② Pinching. In order to keep the crown form unchanged, or to increase the number of flowers of flower-viewing potted trees, pinching can be carried out. Pinching means removing the terminal buds of certain branch tips to inhibit branch elongation and promote branching growth. The specific practice is to promptly remove unnecessary terminal buds and retain terminal buds at good positions. For parts where branches are too sparse, top and pinch to promote more lateral branches and make the plant shape fuller. Pinching should differ according to tree species; for example, Buddhist pine grows several times a year, so pinching must also be carried out several times.

③ Bud removal. After potted trees are pruned or repotted, the trunk and branch spurs will grow many axillary buds. If not attended to and allowed to grow, they will not only destroy the original form of the potted tree but also disperse nutrients, which is unfavorable for growth; at the same time, too many branches also hinder air circulation and sunlight, making pests and diseases likely. Therefore, according to shaping needs, all young buds not to be retained must be removed or cut off. For pines and cypresses, the main buds at the tips of branches should be removed in spring to promote the second regrowth of shorter, more aged pine needles, making them natural and beautiful. For example, branches grown last year, if too long, can also be slightly shortened, and afterward buds will still sprout and branches grow from the needle bundles. But cutting the young branches of pines and cypresses with scissors will make the wound turn rusty; it is better to remove them by hand. For tree species with strong sprouting ability and extremely easy germination, such as elm, Chinese bird plum, Fujian tea, orange jasmine, etc., you must always pay attention to bud removal.

④ Leaf removal. The best viewing period for potted trees is when new leaves have just grown, because at this time the leaves are small, the color is beautiful, lush green as if about to drip, full of vitality. Leaf removal is an effective measure for shaping deciduous trees. Because leaf removal can change a potted tree from sprouting new buds once a year to sprouting twice a year, forming extremely beautiful, fine and dense branches and extending the viewing period. For many tree species such as elm, pomegranate, ginkgo, Chinese hackberry and small-leaved banyan, all the leaves can be removed, and in about twenty days new buds will sprout again on the branches. For potted trees whose leaves are to be removed, fertilize before leaf removal and place them in a place with ample sunlight to promote vigorous growth and improve the leaves' regenerative capacity.

(9) Repotting

Repotting of tree stump bonsai usually means changing the potted tree to new soil; some also call it “repotting and replanting” or “replanting”, “changing pots”. Why must tree stump bonsai be repotted? There are two reasons: first, the condition of the soil changes. Second, the potted tree's root system changes.

Potted trees grow in limited pot soil; after two or three years, the root system gradually grows, the nutrients in the pot soil are absorbed completely by the plant; with years of watering, the soil decreases and the soil in the pot becomes compacted, resulting in poor drainage and air permeability and other drawbacks.

For relatively thick and large tree stump bonsai cultivated for many years, after a relatively long period of growth, the old roots are densely packed and squeeze each other, making it difficult for new roots to grow and obstructing the potted tree's growth; it must be changed to a larger pot with new soil added to increase the soil's nutrient content.

In short, the purpose of repotting is to ensure the normal growth and development of the potted tree.

(1) Repotting Season

Repotting is usually carried out during the period when trees are dormant or developing slowly. Most trees are repotted in spring and autumn. In spring it is usually from late February to about early May, while in autumn it is best from late October to mid-November. But different tree species have different requirements. For example, elm is cold-tolerant, and the best time for repotting is close to before the Beginning of Spring; Fujian tea, orange jasmine, Chinese bird plum, etc. share the characteristic of liking warmth and fearing cold, so repotting should be carried out close to the Summer Solstice; pines, although they both like sunlight and are not afraid of cold, dislike dampness, so repotting is safest around mid-April, because by then the plum rain season is basically over and the weather is not too hot; rhododendrons have strong growth vigor and can be repotted at any time except in the hot summer and winter, but repotting should be done only after viewing the flowers.

As for the service life of pot soil, it should be determined according to the tree's growth vigor and the condition of the pot soil. For vigorous-growing ones whose pot soil still drains and breathes well, repotting may be temporarily unnecessary; for flower-viewing and fruit-viewing bonsai, which consume more nutrients, generally repot once every one to two years; for small-leaved evergreen plants and trees in large pots, because they consume fewer nutrients, repot once every two to three years; for miniature bonsai, because the pot is small and the soil little, repot once a year.

(2) Methods of Repotting

As said above, repotting of tree stump bonsai usually means changing the soil, not the pot. Before repotting, first prepare the potting soil. Because different potted trees have different requirements for soil, before repotting you must, according to the growth characteristics of the potted tree, select and blend suitable potting soil, and then begin.

① Wash the tree pot. When an old or originally used tree pot is used again, it must be washed clean with clear water and then dried in the sun; this can serve to disinfect and sterilize. If it is a newly bought pot, it must be soaked in water for a period before use, both to clean it and to remove its “fire qi”.

② Cover the drainage hole. For the drainage hole at the bottom of the pot, a curved tile piece should be placed over the hole; this both prevents a large amount of pot soil from being lost and also serves to drain water. If it is a tall cylinder or deep pot, in addition to covering with a curved tile piece and leaving more gaps, a layer of coal cinder may also be spread at the lower layer, with the cinder particles relatively coarse, to facilitate drainage.

③ Handle the old soil. Turn the tree out of the pot together with the soil, and use a bamboo stick to remove the old soil mixed among the potted tree's root system. How much old soil to remove should differ according to tree species. For example, for pines about half the old soil can be removed, and then new potting soil added for planting; for elm, pomegranate, rhododendron and other tree species with many fine roots and easy growth, all the old soil can be removed, and new potting soil added for planting.

④ Handle the root system. For potted trees cultivated for one or two years, when turned out of the pot, the fine roots are all over the pot soil; a bamboo stick can be used to slowly remove part of the old soil, cut off all the decayed old roots, and at the same time cut off part of the taproots and newly grown fine roots; there is no need to keep too many or too long, so as not to reduce the pot's soil-holding capacity. For example, the elongated fine roots of pines should be cut off by two-thirds. But for those with poor root development, the old roots may not be removed, so as to consolidate their foundation.

⑤ Plant according to the composition. Generally tree stumps can rarely be viewed from two sides; most are better on one side and inferior on the other, so before planting the viewing side must be determined. Whether the planting position of a tree stump bonsai is appropriate or not directly affects the layout of the tree stump bonsai and its artistic effect. Regardless of tall cylinder, square pot, round pot and various tree styles, from an artistic point of view it is never appropriate to plant the tree stump in the center of the pot. Therefore, when planting, the whole tree and the pot must be laid out as a unified whole, with relative echo and coordination, striving to achieve the artistic conception of gathering like a crouching tiger and dispersing like a roaming dragon. The ratio between the tree and the pot edge should generally be 3:7 or 4:6, that is, it is appropriate for the potted tree to be slightly offset toward any one side of the pot, left, right, front or back. For some large tree-style potted trees with gnarled roots and ancient, vigorous appearance, where the artistic conception requires steadiness and dignity, a slightly more central planting position is also acceptable.

But for cascade-style potted trees, when planted in a tall cylinder or square pot, attention must be paid to their position and the tendency of the center of gravity of the tree head, tree roots, tree momentum and pot shape; there must be the momentum of being in danger but not falling, slanting but not toppling, and the trunk must never press tightly against the pot edge; as far as possible, the corner-pressing method and the corner-offsetting method should be used. The corner-pressing method is to make the head and roots close to the pot edge; the corner-offsetting method is to make the pot corner face slightly toward the viewing side, avoiding stiffness in the potted tree.

(10) Prevention and Control of Common Pests and Diseases

Because bonsai are often placed indoors, where light or ventilation conditions are relatively poor, various pests and diseases often occur; in mild cases the plant becomes thin and weak with few flowers and yellow leaves, and in severe cases the whole plant dies. The active prevention and control approach is based on the principle of “prevent early when there are no pests or diseases, treat early when there are pests or diseases, give priority to prevention, and give priority to treating the root cause”, eliminating pests and diseases at the budding stage so that they do not spread and expand.

(1) Preventive Measures

① Strengthen the maintenance of bonsai and various management tasks. Master scientific methods of fertilizing, watering and pruning; the site must be kept clean and maintain suitable temperature and humidity, so that potted trees have ventilation and light on all sides.

② Use decomposed fertilizer and disinfect the soil. The simplest method of soil disinfection is to stir-fry the pot soil in a pan or expose it thoroughly to the hot sun, to kill pathogenic bacteria and insect eggs in the soil.

③ Spray preventive chemicals. In spring, various potted trees enter the season of vigorous growth; spraying the potted trees with Bordeaux mixture at a concentration of one percent one to three times can prevent pests and diseases. The method of preparing Bordeaux mixture is: dissolve one jin of copper sulfate and one to two jin of quicklime separately in one hundred jin of water, then pour them simultaneously into a third container and stir evenly, and it is ready.

④ Eliminate sources of infection. For all tree stumps dug up from elsewhere or bought, carefully check whether there are pests or diseases. If pests or diseases are found, effective prevention and control measures must be taken quickly. If some potted trees show pests or diseases, they must be isolated immediately to prevent spread. For individual cases that are especially seriously harmful and difficult to control, burn them early or bury them deep, to avoid suffering a big loss for a small gain.

(2) Common Diseases and Their Prevention and Control Methods

Tree stump diseases are generally divided into two major categories: physiological diseases and parasitic diseases.

Physiological diseases are caused by abiotic factors. For example, unsuitable temperature, humidity, soil or fertilizer, or a lack of trace elements and other environmental factors cause physiological disorders and pathological changes.

Parasitic diseases are caused by biological factors. For example, fungi, bacteria, viruses, nematodes, etc. parasitize within the bodies of flowering plants and cause various pathological changes, among which diseases caused by fungi are the most numerous.

Several common diseases and their prevention and control methods are introduced below.

① Powdery mildew. On the leaves, branches, flower stalks and flower buds of affected plants, a layer of powdery white substance grows on the surface. The affected plant is stunted and not luxuriant, the leaves are uneven or curled, the branches develop abnormally, and the flower buds are destroyed, so it cannot flower or produces deformed flowers. In severe cases, the flowers are few and small, the leaves shrivel and dry up, seriously affecting plant growth, to the point that the whole plant dies. The cause of the disease is mostly pot soil that is too wet, too much nitrogen fertilizer, and too long a period of shading.

Prevention and control methods: attention should be paid to ventilation and facing the sun, controlling humidity, cutting off diseased leaves and burning them in a concentrated way; and when the morning dew has not yet dried, spray a small amount of sulfur powder or 0.2 to 0.3 degree lime-sulfur mixture, which can achieve a preventive and control effect.

② Root rot. After stumps dug from the wild are planted in pots, this disease often occurs. Most cases are caused by poor transplanting, plus wounds invaded by pathogens and excessive watering, waterlogged soil, poor aeration, and root suffocation leading to rot. Excessive fertilization can also cause root rot. After the roots rot, the absorptive function is obstructed, causing the above-ground branches to wither and leaves to drop.

Prevention and control methods: carefully dig up the original plant, prune the rotted part of the root system, then replant with new soil, and change the growing conditions of the stump bonsai, increase light, loosen the soil, appropriately control fertilizer and water, and promote its recovery.

③ Leaf mold. In the early stage of the disease, round purplish-brown spots appear on the leaves and expand day by day; the center becomes pale yellowish-brown, the edge purplish-brown, and the lesions have obvious concentric ring patterns. By autumn, the lesions turn dark brown, scorched and brittle, easily cracking, and on them grow dark green mold-like substances. In severe cases, the lesions often spread from the lower leaves of the plant to all the leaves of the whole plant, causing a large number of scorched leaves and affecting growth and flowering the following year. The cause of the disease is mostly poor management, such as high humidity or the plant being affected by freezing, after which this disease occurs more often.

Prevention and control methods: mainly strengthen management, pay attention to pruning, keep the plant ventilated and exposed to light, and keep the soil dry and refreshing. Promptly clean up diseased leaves and diseased dead branches and burn them. It can also be prevented by spraying once a week in early spring and early autumn with 120 to 160 times equal Bordeaux mixture or 65 percent zineb wettable powder at 500 to 600 times dilution.

(3) Common Pests and Their Control Methods

① Eucleid moths. From June to October each year, eucleid moths feed heavily on the leaves of potted trees; in severe cases they can eat all the leaves, causing the trees to wither and die. Most eucleid moths produce two generations per year, overwintering as mature larvae inside their cocoons.

Control methods: First, remove the overwintering cocoons, cut off young larvae and egg masses, or set up lights at night to trap and kill them. Second, when larvae are at peak outbreak, spray with 90% trichlorfon at 1,000 times dilution, or mix and spray with 6% wettable benzene hexachloride at 200 times dilution.

② Bagworms. Bagworms are commonly known as “bag worms” or “case worms.” From June to October each year, they gnaw the leaves and branch tips of potted trees. They can survive in harsh environments such as hunger and drought. Especially the nearly mature larvae, which often hide for several days without eating and still do not die.

Control methods: Same as for eucleid moths, but because they are wrapped in a skin-like case, chemical spraying is difficult to effective. If their numbers are small, it is best to catch them by hand.

③ Longhorn beetles. Longhorn beetles produce one generation every one to two years, overwintering as larvae inside the tree trunk. Newly hatched larvae tunnel and feed under the bark, then bore into the trunk and roots, where they then pupate. Adults begin emerging in late May and feed on branch tips and tender leaves. Potted trees damaged by them often end up dying.

Control methods: Catch and kill adults, crush eggs. For those that have bored into the wood, use a steel wire to hook them to death; or soak a cotton ball in dichlorvos, stuff it into the bore hole, and seal the opening with yellow mud; or drip dimethoate diluted 5 to 10 times with water into the bore hole to poison the larvae. You can also cut off the damaged branches and immediately burn or deeply bury them.

④ Scale insects. Common ones include the cottony cushion scale and the armored scale. The cottony cushion scale has white waxy filamentous hairs; the armored scale is shield-shaped and brown. Scale insects mainly suck the sap from the branches and leaves of potted trees, causing poor growth and even death of the entire plant. The secretions excreted by scale insects clog the leaf stomata and often cause sooty mold.

Control methods: In the early stage of larval hatching, spray with dichlorvos at 800 to 1,500 times dilution, or use a brush dipped in water to brush the insects off the potted tree and kill them. In addition, prune appropriately to allow ventilation and light penetration through branches and leaves.

⑤ Aphids. Aphids are small, appearing in green, brown, red, black, gray, and other colors. They have a very strong reproductive capacity, reaching 10 to 30 generations per year, with the breeding period from around March to October each year. These insects gather on the young tender branches and leaves of trees, sucking nutrients, causing tender shoots to shrivel, tender leaves to curl, and tumor-like protrusions to form, and they attract ants and transmit other diseases.

Control methods: Spray with dimethoate emulsion at 1,000 to 2,000 times dilution or dichlorvos at 1,500 to 2,000 times dilution. However, elm, Chinese hackberry, pomegranate, and others are sensitive to dimethoate and will drop their leaves after spraying, so switch to derris extract at 1,000 times dilution or other chemicals for spraying.

⑥ Red spider mites. Red spider mites are small, usually red. In high-temperature and dry environments, they reproduce especially quickly, producing 7 to 14 generations per year, and almost all potted trees suffer from their damage. They like to spin webs on plants and suck sap beneath the webs; affected leaves turn yellow and fall, affecting the tree's vigor, and some even cause the entire plant to die.

Control methods: Spray with dimethoate or dichlorvos at 1,500 to 2,000 times dilution, and also pay attention to increasing air humidity.

⑦ Snails. Snails mainly bite through tender branches, affecting plant growth.

Control methods: Snails like moisture, so catch and kill them in the early morning or on rainy days. On sunny days, sprinkle some lime powder around the pot, which can also achieve a certain control effect.

⑧ Ants. Ants damage young buds and sometimes build nests in the potting soil, harming fine roots.

Control methods: Ordinarily, sprinkle some lime powder at the base of the pot, or spray diluted insecticide. If there are nests in the potting soil, repeatedly lure them out with sugar and kill them with fire or boiling water; you can also soak the potted tree in water for a period to drown or drive away the ants. You can also pour a small amount of diluted dichlorvos solution into the soil to kill them. If none of the above methods can completely eradicate them, then you have no choice but to pull up the potted tree, remove the old soil and roots, disinfect the pot, and replant with fresh soil, with strengthened management afterward.

⑨ Underground pests. Mainly cutworms, which produce four generations per year, overwintering as pupae or mature larvae in the soil, with adults emerging in mid-March. Both adult moths and larvae feed on the tender stems and leaves of flower and tree seedlings, causing the potted trees to die.

Control methods: When changing the soil and repotting, eliminate eggs and larvae, and spray with tea seed cake water at 6 to 10 times dilution or 15% malathion at 800 times dilution.

(4) Commonly Used Chemicals and Their Application Rates

① Trichlorfon. Trichlorfon is a highly effective, low-toxicity insecticide, with low toxicity to humans and livestock, and it is not easily absorbed through the skin. Trichlorfon has strong stomach poison and contact-killing effects, and is most effective against pests of Diptera, Hymenoptera, Coleoptera, and others. It can be used to control caterpillars, leaf roller moths, eucleid moths, and many other pests with very good results. However, its control effect against pests such as aphids and red spider mites is relatively poor.

Trichlorfon formulations include 2.2% powder, 50% and 80% soluble powders. The concentration generally used for trichlorfon is around 0.1%, and the diluted solution should be prepared and used immediately.

② Dichlorvos. Dichlorvos is a highly effective, highly toxic insecticide, with moderate toxicity to humans and livestock. It has fumigant, stomach poison, and contact-killing effects on pests, and has good control effects on both chewing-mouthpart pests and piercing-sucking mouthpart pests. Dichlorvos is highly volatile with a high vapor pressure, giving it a strong knockdown effect on pests. Dichlorvos decomposes easily after application and has a short residual period.

Dichlorvos formulations include 50% emulsifiable concentrate, 80% emulsifiable concentrate, and 60% dichlorvos plus 20% dimethoate mixed emulsifiable concentrate.

The application rates are: 50% emulsifiable concentrate diluted with clean water to 1,000 to 1,500 times dilution, or 80% emulsifiable concentrate at 2,000 to 3,000 times dilution, or 60% dichlorvos plus 20% dimethoate mixed emulsifiable concentrate at 2,000 to 3,000 times dilution for spraying, which can effectively control aphids, red spider mites, leafhoppers, leaf roller moths, and other pests. You can also use 80% emulsifiable concentrate diluted with water to 1,000 times dilution for spraying, which can control various eucleid moths and scale insects.

Dichlorvos emulsifiable concentrate is volatile, so the solution should be prepared and used immediately, but the dosage must be strictly controlled, and the concentration should not be too high to avoid phytotoxicity.

③ Dimethoate. Dimethoate is a highly effective, low-toxicity insecticide with high contact-killing efficacy and systemic properties. In particular, its toxicity to pests increases significantly as the temperature rises, so the spraying concentration should be determined according to the temperature. It can be mixed with general insecticides and fungicides, but must not be mixed with alkaline chemicals. Dimethoate is suitable for controlling many pests, and has very good control effects on common pests of potted trees, such as eucleid moths, aphids, red spider mites, and various piercing-sucking and chewing mouthpart pests.

Dimethoate formulations include 20% emulsifiable concentrate, 40% emulsifiable concentrate, 60% soluble powder, 1.5% crystalline technical powder, and 2% crystalline technical powder.

Use 40% dimethoate emulsifiable concentrate diluted with clean water to 1,000 to 1,500 times dilution, or 60% soluble powder diluted with water to 1,500 to 2,000 times dilution for spraying; the effect can last about ten days, with notable results against common pests.

Dimethoate is stable to sunlight, but moisture easily causes decomposition, so it will slowly decompose during storage. Among potted trees, elm, Chinese hackberry, pomegranate, and other plants are sensitive to dimethoate and are not suitable for use in pest control, otherwise it will cause early leaf drop.

④ Fenitrothion (sumithion). Fenitrothion has a broad insecticidal range and strong contact-killing and stomach poison effects on piercing-sucking mouthpart, chewing mouthpart, and boring pests. It has no systemic action, but has good penetrative properties in plant tissues, and has relatively low toxicity to humans and livestock.

Fenitrothion formulations include 2% powder and 50% emulsifiable concentrate.

Use 50% emulsifiable concentrate diluted with clean water to 1,000 to 1,500 times dilution for spraying, which can effectively control eucleid moths, red spider mites, caterpillars, and various scale insects.

But note that it must not be mixed with strongly alkaline chemicals. If it needs to be mixed with Bordeaux mixture, it should be mixed temporarily just before application.

⑤ Phosmet. Phosmet is an insecticide with low toxicity to humans and livestock, has a broad insecticidal range, acts mainly by contact, and has a short residual period.

Phosmet formulations include 2.5% powder, 25% wettable powder, and 25% emulsifiable concentrate.

Use 25% emulsifiable concentrate or 25% wettable powder diluted with clean water to 1,000 times dilution for spraying to control red spider mites, aphids, and others; use 800 to 1,000 times dilution to control eucleid moths and other pests; use 400 to 600 times dilution to control scale insects and many other pests.

Phosmet can be mixed with DDT, but must not be mixed with Bordeaux mixture. After use, hands, feet, and face must be washed to prevent effects on the human body.