What to Do When the Tips of Podocarpus Branches Die Back? Causes and Control Methods
Podocarpus is a high-quality ornamental plant that most families are very fond of. However, some podocarpus develop the following symptom during cultivation: the color of the tips of young leaves begins to change from red to light brown and then grayish white, eventually causing all the leaves at the entire branch tip to die.
The cause of leaf tip dieback in podocarpus is mostly fungal infection of the branch tips during hot, rainy seasons. If podocarpus plants grow leggy, with tender tissues, if seedlings are too densely planted with poor ventilation, or if wounds form from sunscald, they are all easily infected by pathogens that trigger this disease. The control methods are:
(1) Remove dead branches and diseased leaves and burn them to reduce sources of infection.
(2) When propagating, select disease-free, robust branches as propagation material.
(3) Protect plants from various mechanical injuries and from frost damage, sunscald and wind damage, which can reduce the occurrence of this disease.
(4) Before the disease occurs, spray with 75% chlorothalonil wettable powder at 500 times dilution, or Bordeaux mixture at 1:1:100, once every 2 weeks, which can effectively prevent the disease.
Care of Podocarpus Bonsai and Appreciation of Podocarpus Bonsai Pictures
Care of Podocarpus Bonsai and Appreciation of Podocarpus Bonsai Pictures
Podocarpus is an evergreen plant that loves sunlight yet tolerates shade, making it a fairly ideal plant for indoor decoration. It has a certain resistance to pests and diseases.
I. Propagation and Cultivation:
Podocarpus can be propagated by sowing or by cuttings, and seeds should be sown as soon as they are collected.
Cuttings can be taken as long as podocarpus is in its growing period, but spring and autumn are the main seasons, with May and June being better. Choose current-year, slightly lignified branches as cuttings. The author took cuttings of a batch of podocarpus seedlings;
Method of operation: First prepare a seedbed with a total height of 30 cm, in three layers: the bottom layer 10 cm of cinders, 07 cm of coarse sand, and 13 cm of picked-over and sifted sterile mountain soil or vegetable garden soil. Cut the branches into lengths of about 10 cm, remove the needles below the tip, and treat them with vitamin P12 injection. After two minutes, the branches can be inserted into the prepared seedbed and watered thoroughly. After that, keep them moist and frequently mist the leaves; when the sun is strong and temperatures are high, a shade frame must be set up; at night, open the shade frame to let the branches receive dew, and when hot, dry weather occurs, water must also be sprayed around the seedbed to lower the temperature. As long as reasonable daily management is adopted, the main roots will heal and the plants will survive in 60 to 70 days; in the same year the branches can grow to about 07 to 10 cm tall, and the following year they can be potted for management.
To make the seedlings grow faster, they can be left in the bed for cultivation, but the surviving seedlings need to be divided and transplanted sparsely. After several years they can be put into bonsai for shaping, or shaping can be done in the seedbed. While potting, shaping can be done artificially according to the tree form, keeping the terminal buds or useful lateral branch buds on the trunk and removing all other branches and buds. Benefits: a. it reduces water consumption; b. it promotes thickening of the trunk; c. it highlights the beauty of the trunk. After the tree stump has taken shape, as long as the tree form is pruned every year, the stump can keep growing year by year.
II. Shaping and Fixing the Posture:
01. Types of shaping: there are the following types: cascade style; large cascade style; semi-cascade style; slanting trunk style; curved trunk style; group planting style, etc. During shaping, artistic processing must be based on the natural beauty of the seedling itself, adapting measures to the material and adding beauty to beauty, so that the shape is strong and powerful with distinct layers.
02. Shaping tools: bamboo sticks, iron wire, copper wire, plastic tape, hemp rope, etc. can be used.
03. Shaping procedure: during operation, according to the thickness of the branch—
01) Choose iron wire. Thicker branches are more difficult to shape; a thicker iron wire can be placed against the branch, and plastic tape used to bind the iron wire and branch together, then bend the bound branch by hand according to one's will for shaping. After about half a year or a year, untie the iron wire; by then, after a year of growth, the branch willset its shape；
02) For branches that are difficult to shape, a cut can be made: cut a small slit with a knife at the main point to be bent, so the branch can be bent down. After bending, the wound must be wrapped with moss or sterile soil to let the wound heal.
03) Root-lifting shaping: after the whole stump has grown for many years, the roots can be lifted when repotting. Method of operation:
Turn the stump to be repotted out of the pot; when moving it into a new pot, lift the root crown and add more organic potting soil. When the stump resumes normal growth, wash away the soil from the root crown and the pot surface with water, and the roots will be exposed.
After several years of growth, the roots exposed on the pot surface undergo photosynthesis and, through sun by day and dew by night, all form a vigorous, ancient and elegant posture, making the whole stump appear powerful and vigorous. After that, as long as reasonable bud pinching and pruning are carried out during the vigorous growth periods in spring and autumn, the branches and leaves will grow thick, long and dense.
04) Shaping techniques: shaping by pruning is relatively simple; shaping techniques such as tying, pressing, binding and hanging are more difficult and place higher demands on the shaper's artistic imagination, operational skill and the condition of the tree's trunk and branches. During shaping, artistic processing must be based on the natural beauty of the seedling itself, that is, measures must be adapted to the tree and beauty added to beauty, so that the shape is strong and powerful with distinct layers.
A. Pruning: taking advantage of podocarpus's tolerance of pruning and its small leaf shape, various shapes can be made, such as—
spherical, conical, multi-layered spherical, etc., simply by pruning according to a pre-designed pattern.
When pruning a three-layered spherical shape, first select a seedling with an obvious trunk and a relatively good upright form.
If the pruning design is a three-layered spherical shape with a total height of 2 m, then the lower layer is about 50 cm high, the middle layer about 40 cm high, and the top layer 30 cm high; all branches on the trunk must be cut away in the 45 cm between the first and second layers and the 35 cm between the second and third layers, and then the three spheres are pruned. It is best if the upper, middle and lower spheres gradually increase in size, so as to seek harmonious proportions and better ornamental value. Generally, pruning is suitable when new shoots have grown 20-30 cm, and multiple prunings are needed to make each layer's sphere round, full and compact.
B. Tying: for shaping by tying, sturdy bamboo sticks and tough hemp rope can be used. Bind the bamboo stick and branch tightly and firmly with hemp rope; then fix one end of the bamboo stick to the trunk, so that by adjusting the direction of the bamboo stick, the branch grows in a specific direction according to the shaper's wishes, achieving the purpose of shaping. Note that shaping by tying is suitable for younger podocarpus; older podocarpus, because of its thick branches, is difficult to shape and gives poor results.
C. Pressing: shaping by pressing mainly uses the method of bending and tilting the trunk so that the tree body on a slant presents an artistic beauty completely different from that of an upright plane. Because the branches of podocarpus resemble human arms, and the leaves clustered into hemispherical shapes growing at the tops of the branches resemble human palms, together with the bent tree body, it looks like a greeter bending at the waist and arms to welcome guests, very vivid and lifelike. Note: after bending the tree body, a wooden stake must be used to support the tilted end to prevent the tree body from lodging due to excessive tilting, and straw of moderate thickness should be placed between the contact surfaces of the wooden stake and the tree body to avoid injury to the tree.
05) Shaping techniques:
Podocarpus leaves stay evergreen all year round, the leaves are small and dense, the branches are short, and the trunk is vigorous; it has a long lifespan and tolerates pruning, making it one of the good materials for making bonsai. Because podocarpus grows slowly, stump bonsai also take shape slowly. Good podocarpus bonsai are rare and highly sought after. In order to produce podocarpus stump bonsai in greater quantity and more quickly, we tried remedial modification on some stumps that had a relatively good trunk form but lacked branches and small pads, striving to make their forms perfect. Over several years and through much practice, we have summarized some experience, and the relevant technical essentials are introduced below:
A. Method for compensating for missing branches at the exposed base: some podocarpus stump bonsai have good trunk movement and branch pads, but lack lower branch pads, or a piece of inferior podocarpus material has a plastic trunk and sufficient branches in the upper part, but no branches on the lower part of the trunk, which brings certain difficulty to training and shaping. If lower branches are regrown, it is absolutely difficult to make the upper and lower branches proportionate, and it takes a very long time. To solve this problem, we tried the approach-grafting method using small trees, with good results.
Method: choose a small tree that is robust, with luxuriant branches and leaves and a suitable trunk thickness, and pot it or transplant it beside the large tree where branches need to be compensated. In the western Sichuan region, approach grafting is carried out in March and April (temperature 15°C-22°C). After grafting, both the large tree and the small tree are managed normally, and according to the growth of the small tree's branches and the healing situation, they are cut off in two stages; after the approach-grafted branches have completely survived, pruning or wiring and shaping can be carried out as needed.
Using this method, young saplings can be grafted onto any imperfect part of a podocarpus tree. Through such compensation, the overall shape of the podocarpus bonsai can approach perfection, raising the ornamental value of the bonsai.
B. Root compensation method: some podocarpus, due to waterlogging or other damage, are seriously damaged and their growth is directly affected. If rescue is not timely, they may easily die. In such cases, the method of rescue and compensation is: in March and April, choose a young tree that is robust and has a well-developed root system, transplant it beside the large tree, and approach-graft the middle-lower part of the small tree's trunk to the base of the large tree. As long as the cambium layers are properly aligned during the process, fixed and sealed with plastic film, the success rate can reach more than 95%.
After the graft has survived, cut off the upper part of the young tree. In this way, the roots of this young tree become the roots of the large tree; if the stump is relatively large, or the root damage is severe, several young trees can be grafted at different orientations at the same time to increase the root system, or even completely replace the original tree's root system. Using this method, the root shape of podocarpus bonsai can also be changed, giving the exposed root system the effect of hanging roots and clawing feet.
C. Sectional shaping method for the trunk: some podocarpus that have already become large trees have damaged branches, shrunken crowns, rotten roots and extremely poor growth due to various reasons, useless to keep yet a pity to discard. In such cases, the sectional shaping method can be adopted to turn waste into treasure. The method is: according to the form of the tree's trunk, saw it into several sections. Fix the sawed-off trunk sections in the soil with three wooden sticks, first use the root compensation method to graft roots onto the lower part of the trunk section, then use the missing-branch compensation method to graft upper branches at suitable positions on the trunk. After the grafted roots and branches have survived, shape them by pruning and wiring. After two or three years, a well-shaped, robustly growing podocarpus stump bonsai will appear before us. After modification, the artistic ornamental value and economic value of the podocarpus will both increase substantially.
III. Care and Management:
01. Light: podocarpus is a neutral to shade-leaning tree species; it can accept relatively strong light and can also grow in relatively shady environments. Although the summer temperature in the Shunde area is relatively high and the sunlight intense, because large podocarpus trees under high temperature and strong light are helped in maintaining their tree posture and leaf shape, there is no need to shade large podocarpus trees in summer in the Shunde area either. However, because podocarpus seedlings have tender tissues, they should not be exposed to strong light for long periods, and it is recommended to keep them under tree shade for care.
02. Watering: podocarpus is not a member of the pine family and is not drought-tolerant. On the contrary, podocarpus tolerates shade and moisture, and during the growing period it should be watered frequently, but it should not be waterlogged. In the Shunde area on sunny summer days, attention should be paid to frequent watering, generally once in the morning and once in the evening, and in addition the leaves should be misted frequently so that the leaf color is fresh green and growth is good. Summer rainfall is usually also relatively abundant, and podocarpus is not tolerant of waterlogging, so care should be taken to prevent prolonged water accumulation.
03. Fertilizing: podocarpus likes fertilizer, so fertilizer should be applied thinly and frequently, mainly nitrogen fertilizer, and an appropriate amount of black alum can be added and fermented into alum fertilizer water. During the growing period, fertilize once every 1-2 months; fertilizing can be done together with watering (water-to-fertilizer ratio of 9:1). For large-area block planting, the semicircular trench application method can be used, applying 300-500 g of quick-soluble compound fertilizer each time. For potted plants, a water-soluble fertilizer containing 0.5%-1.0% compound fertilizer or a thin cake liquid fertilizer can be sprayed each time.
04. Repotting: bonsai or potted podocarpus can be repotted once every three to four years. Repotting is best done before buds break in spring, and can also be done in autumn. Base fertilizer soil should be placed at the bottom of the pot; artificially prepared potting soil can be used. Fertilizing should be done during the growing period, and the fertilizer can be decomposed human manure or bean cake, etc.
05. Pest and disease prevention: podocarpus is naturally easy to grow and convenient to manage, but attention must be paid to preventing the three major pests and diseases: leaf blight, new-leaf aphid and scale insect, so as to ensure healthy growth of podocarpus. The author has summarized the planting experience of various flower and tree nurseries and introduces the disease characteristics and key control points of the following three pests and diseases.
01) Leaf blight: podocarpus leaf blight is the most headache-inducing problem for many flower growers. This disease mainly occurs on the young leaves at the branch tips of podocarpus. After infection, the leaf color turns red, and the lesions are irregular, spreading from the leaf tip toward the leaf base, causing the distal half of the leaf to die. In the later stage the lesions are light brown. As the disease develops, small black spots appear on both the front and back of the diseased parts of the leaves in the later stage, seriously affecting the growth and ornamental value of podocarpus. The pathogen overwinters as mycelium in dead branches and fallen leaves. In the second spring, the pathogen invades young leaves or enters branches through wounds. Generally speaking, conditions such as overly dense cultivation, poor ventilation, extensive management and wounds caused by sunscald can all promote the disease, and it is more likely to occur in April-May and August-September.
Control methods: In winter, cut off dead branches and severely diseased leaves and remove diseased leaves on the ground surface for centralized destruction. Strengthening care and management can enhance the plant's disease resistance. In the early stage of the disease, spray fungicides such as 1000 times dilution of amobam, 500 times dilution of 75% chlorothalonil, or equal-amount 100 times Bordeaux mixture for control, spraying once every 7-10 days for 2-3 consecutive times to prevent the disease.
02) New-leaf aphid: the new-leaf aphid is a common pest on podocarpus. Its body is reddish brown or reddish purple, oval-shaped. It is about 1.3 mm long and about 0.6 mm wide, with a truncate cornicle located on a brown cone. The cauda is papillary and distinctly protrudes from the end of the abdomen. Adults and nymphs gather on the young shoots and the undersides of young leaves of podocarpus to suck sap, causing poor growth of young shoots, smaller leaves, yellowing leaf color and weakened tree vigor. The podocarpus new-leaf aphid overwinters as eggs on branches. In April of the following year, the overwintering eggs hatch into nymphs, which gather on new shoots to cause damage, reaching the peak of reproduction in May-June, when damage is most severe. After July, due to high temperatures, the population density drops markedly, and after the weather turns cool the population rises again. In October, female aphids and male aphids are produced, and after mating they lay eggs, which then overwinter.
Control methods: In early spring, before podocarpus has budded, spray lime sulfur mixture at 1-3 degrees Baumé to kill overwintering eggs. And in late April, when the overwintering eggs are finished and nymphs are beginning to cause damage, spray 50% pirimicarb wettable powder at 600-800 times dilution, or 25% sulfuli at 1000-1500 times dilution.
03) Scale insect: this is also a relatively stubborn pest on podocarpus, with adults and nymphs damaging podocarpus. The adult scale is 2.5 mm long, brown, with the center of the scale raised into a hemispherical shape and a smooth surface; nymphs are light yellow or pale pink, and newly hatched nymphs have a ridged, semi-transparent back. Scale insects mainly gather on the young and tender parts of podocarpus such as leaves, petioles and young stems, sucking plant sap, worsening the host's nutritional condition, causing leaf chlorosis and poor plant growth. Scale insects have 3 generations a year and overwinter as adults and nymphs on the damaged parts of the host. In the Guangdong region, the hatching periods of scale insects are late March and late June respectively.
Control methods: Remove scale insects from leaves and branches by manual scraping or wiping. During the nymph hatching period, choose 40% profenofos EC at 1500 times dilution, or 2.5% deltamethrin EC at 4000 times dilution for spray control, and be sure to spray the solution onto the undersides of the leaves.
04) Podocarpus has relatively few pests and diseases, but in hot, dry summer seasons attention should be paid to controlling red spider mites. Red spider mites gather as adult mites, nymph mites and larval mites near the veins and at the leaf margins of podocarpus leaves and on young branches to suck sap. The upper surface of damaged leaves shows many powdery green spots, which later become grayish white small spots, losing their original luster, and in severe cases the whole leaf turns grayish white.
Control methods: during the peak period of red spider mites (May-September), spray some insecticides for treating red spider mites, such as pyridaben, hexythiazox, fenbutatin oxide, etc., once every 10 days, using the concentration according to the instructions.
IV. Identifying Que She Podocarpus：
Podocarpus belongs to the family Podocarpaceae, genus Podocarpus. It is evergreen all year round, vigorous and elegant, and Que She podocarpus in particular is even more beloved, occupying an unusual position in our country's potted plant art.
Que She podocarpus is a variety of podocarpus, and its main differences from large-leaf podocarpus or medium-leaf podocarpus are:
Large-leaf podocarpus is a large tree; medium-leaf podocarpus is a sub-tree; Que She podocarpus is a small shrub. Currently on the flower and tree market, some people often use seedlings of medium-leaf podocarpus to pass them off as Que She podocarpus for sale. Que She podocarpus is relatively difficult to distinguish as genuine or fake at the seedling stage, and generally "four looks" are needed:
First look at the leaves: Que She podocarpus has small leaves with rounded tips, shaped like a sparrow's tongue; the leaf tips of large-leaf and medium-leaf podocarpus are generally more pointed; Que She podocarpus leaves are thicker than the former two, and especially the midrib is distinctly raised.
Second look at the stem: large-leaf and medium-leaf podocarpus are green in color; Que She podocarpus is darker, appearing deep green.
Third look at the nodes: Que She podocarpus produces one flush of shoots in spring and one in autumn, with one node per spring and autumn shoot, the nodes are dense and the resting nodes are obvious, and the combined length of the two shoots in a year is at most only half an inch; large-leaf and medium-leaf podocarpus have long internodes and grow quickly, and their resting nodes are not as obvious as those of Que She podocarpus.
Fourth look at the shoots: the spring shoot leaves of Que She podocarpus are densely borne, shaped like a chrysanthemum heart, which large-leaf and medium-leaf podocarpus do not have, but the autumn shoot buds spread out and do not form a chrysanthemum heart, so it is relatively difficult to identify.
How to grow podocarpus bonsai?
Podocarpus is also known as tu shan, jin qian song, luo han shan, etc. It is an evergreen coniferous tree of the family Podocarpaceae, genus Podocarpus, native to our country and widely cultivated in the Yangtze River basin and the southeastern coastal areas. It has extremely high ornamental value, and its wood is fine and uniform, easy to process, and has medicinal value. It can be used for furniture, utensils, stationery and farm tools, etc. Now let us take a look at the cultivation methods of podocarpus!
Growth habits of podocarpus
Podocarpus likes a warm, humid climate, has weak cold tolerance and strong shade tolerance, and prefers well-drained, moist sandy loam. It is highly adaptable to soil and can even survive on saline-alkali soil. It has relatively strong resistance to various polluting gases such as sulfur dioxide, hydrogen sulfide and nitrogen oxides, and strong resistance to pests and diseases. In our country it is produced in Jiangsu, Zhejiang, Fujian, Anhui, Jiangxi, Hunan, Sichuan, Yunnan, Guizhou, Guangxi, Guangdong and other places. It is cultivated in courtyards as an ornamental tree, and wild trees are very few.
Propagation methods of podocarpus
1. Sowing: podocarpus can be propagated by sowing in August, usually in an open-air seedbed, sown as soon as collected, covered with straw, with attention to shading, keeping the substrate moist, and covering with plastic film in winter to prevent freezing.
2. Cuttings: podocarpus can be propagated by cuttings in spring and autumn. For spring cuttings in mid-March, select 1-year-old robust dormant branches as cuttings. For autumn cuttings in July-August, select semi-lignified green branches as cuttings. The cuttings should all have a heel, with attention to shading, and March is the most suitable time for transplanting.
Cultivation methods of podocarpus
1. Soil: podocarpus cultivation requires a slightly acidic potting soil rich in humus, loose and fertile with good drainage. In alkaline soil the leaves turn yellow and growth is slow. It has a long lifespan, reaching several hundred years, or even more than a thousand years.
2. Watering: podocarpus is not a member of the pine family and is not drought-tolerant. On the contrary, podocarpus tolerates shade and moisture, and during the growing period it should be watered frequently, but it should not be waterlogged. In the Shunde area on sunny summer days, attention should be paid to frequent watering, generally once in the morning and once in the evening, and in addition the leaves should be misted frequently so that the leaf color is fresh green and growth is good. Summer rainfall is usually also relatively abundant, and podocarpus is not tolerant of waterlogging, so care should be taken to prevent prolonged water accumulation.
3. Sunlight: podocarpus is a neutral to shade-leaning tree species; it can accept relatively strong light and can also grow in relatively shady environments. Although the summer temperature is relatively high and the sunlight intense, because large podocarpus trees under high temperature and strong light are helped in maintaining their tree posture and leaf shape, there is no need to shade large podocarpus trees in summer either. However, because podocarpus seedlings have tender tissues, they should not be exposed to strong light for long periods, and it is recommended to keep them under tree shade for care.
4. Temperature: in northern regions, potted podocarpus is suitable; when the outdoor temperature stabilizes at around 10°C, move it outdoors to a wind-sheltered, sunny place for care, and after summer begins move it to a semi-shady place. In winter, when the temperature does not drop to 5°C, it should be moved indoors, and after being brought indoors watering should be controlled; as long as it does not freeze, it can overwinter safely.
5. Fertilizing: podocarpus likes fertilizer, so fertilizer should be applied thinly and frequently, mainly nitrogen fertilizer, and an appropriate amount of black alum can be added and fermented into alum fertilizer water. During the growing period, fertilize once every 1-2 months; fertilizing can be done together with watering (water-to-fertilizer ratio of 9:1).
6. Pests: podocarpus is mainly harmed by leaf spot disease and anthracnose, which can be sprayed with 50% thiophanate-methyl wettable powder at 500 times dilution. Pests include scale insects, red spider mites and bagworms, which can be killed by spraying 40% omethoate EC at 1500 times dilution.
Notes on cultivating podocarpus
1. During the growing season, it is better for the potting soil of podocarpus to be slightly dry. If watering is excessive and the potting soil stays wet for a long time, it will cause root rot and yellow leaves. In severe cases, a large number of leaves fall off and the plant eventually dies. But in summer the water requirement is greater, so watering should be sufficient; if the potting soil is too dry, the leaves easily scorch.
2. During the growing period, attention should be paid to pruning and pinching the already shaped plants to prevent leggy growth of branches and leaves and to maintain the graceful posture of podocarpus. When repotting, care should be taken to cut off excess roots and rotten fibrous roots, and at the same time cut off overly dense branches and leggy branches.
3. In winter, when the outdoor temperature drops to 5°C, it should be moved indoors, and after being brought indoors watering should be controlled and fertilizing stopped. Generally repot once every 2 years, and repotting can be done in either spring or autumn. When repotting, take care to properly cut off excessive roots and decayed fibrous roots, and at the same time cut off overly dense branches and add new potting soil.
4. Potted podocarpus should usually be placed on a high platform or stone pedestal, which can reduce ants, earthworms and other insects crawling into the pot through the bottom hole and harming the plant.
5. When planting podocarpus, take care that the root system is spread out, cover with soil to 2 cm below the pot rim, water thoroughly once, place the pot in a shaded, ventilated place, and let the seedling recover for 7 to 10 days; after the podocarpus has regained vitality, move it to a sunny, moist environment, keep the potting soil moist, and let it grow vigorously.
6. The cause of leaf tip dieback in podocarpus is mostly fungal infection of the branch tips during hot, rainy seasons. If podocarpus plants grow leggy, with tender tissues, if seedlings are too densely planted with poor ventilation, or if wounds form from sunscald, they are all easily infected by pathogens that trigger this disease.