How to grow a Chinese privet (Ligustrum sinense) bonsai? Detailed care tips
The appearance of yin-yang branches: Chinese privet bonsai may encounter the situation of yin-yang branches. So-called yin-yang branches refer to the phenomenon where the same branch of the plant is half alive and half dead, as if yin and yang appear at the same time. Yin-yang branches look awkward and unattractive, so this situation should draw everyone's attention
The appearance of yin-yang branches
Chinese privet bonsai may encounter the situation of yin-yang branches. So-called yin-yang branches refer to the phenomenon where the same branch of the plant is half alive and half dead, as if yin and yang appear at the same time. Yin-yang branches look awkward and unattractive, so this situation should draw everyone's attention. You can combine the bonsai's styling and reserve new branches on both the upper cut and the lower cut of the Chinese privet, so that yin-yang branches can be prevented from appearing.
Preventing branch loss
Branch loss is a problem more commonly encountered with Chinese privet bonsai. Because the bark of Chinese privet bonsai is relatively thin, water supply becomes insufficient, causing old branches to die, and branch loss then occurs. To prevent branch loss, you can pre-grow new growing branches below the cut, so that the reduced branches can continue photosynthesis, and the Chinese privet also avoids branch loss.
Do you know how to solve the problems encountered with Chinese privet bonsai? Next time you run into something similar, there is no need to panic! In fact, Chinese privet can not only be made into bonsai to beautify the environment; did you know about its medicinal value?
Sharing miniature bonsai cultivation and production techniques
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Miniature bonsai are probably very familiar to everyone. After all, in modern social life, this kind of plant bonsai is very common, and the vast majority of friends greatly love them. But for people, miniature bonsai are familiar and known, yet when it comes to understanding them, very few people do. For example, few people know about miniature bonsai cultivation and production techniques. So below let us take a look at miniature bonsai cultivation and production techniques and learn about them together.
¤ Miniature bonsai cultivation and production techniques: Material selection
Miniature bonsai are all very tiny, so not all plants can be used. Generally, you choose plants with relatively small branches and leaves that are easy to survive when potted, have beautiful natural posture and gorgeous flowers and fruits, such as five-needle pine, Buddhist pine (Podocarpus macrophyllus), black pine, phoenix-tail bamboo, fine-leaf holly, asparagus fern and nandina. When selecting materials, choose robust and beautiful branches or seeds of these plants for growing. When they have grown, dig them out for styling and plant them in flower pots.
¤ Miniature bonsai cultivation and production techniques: Styling
Styling of miniature bonsai is very important. Whether a bonsai is beautiful or not depends on whether the styling is suitable, and this needs to be analyzed on a case-by-case basis. Styling emphasizes having the idea in mind before starting. You can make miniature adjustments according to the plant's natural growth tendency, or you can completely transform the plant to create an antique, generous or delicate and beautiful shape. However, when styling, note that after 1 to 2 years the trunk has basically taken shape, and only then can the previously attached lead wire be removed. Unwanted messy branches should be cut off.
The styling of miniature bonsai is very diverse. Common ones include the trunk style, slanting trunk style and cascade style. Among them, the trunk style is very common in miniature bonsai; the plant is generally a straight trunk, so the plant's upright, straight state is maintained without wiring, highlighting the plant's upright beauty. The slanting trunk style requires the plant's trunk to be slightly tilted, making the plant look especially flavorful. The cascade style is common; lead wire is wrapped around the trunk to bend it into shape, and it has great artistic appreciation value.
¤ Miniature bonsai cultivation and production techniques: Potting
Moving a styled plant into a flower pot is the step of potting a plant bonsai. Note that when shaping the plant, the whole plant should be moved out of the clay pot and placed into another prepared flower pot. At the same time, note that when transplanting, the flower pot must be suitable. First, it must suit the plant's dimensions and size so that the transplanted plant can grow normally; second, the flower pot must look good, and the flower pot's shape and color must coordinate with the plant, so that the flower pot can set off the plant.
¤ Miniature bonsai cultivation and production techniques: Care
Miniature bonsai are very delicate, and daily care must be meticulous. The soil in the flower pot must be kept moist, usually watering when dry and stopping when wet. Place it in a relatively shady spot as much as possible; it should not be exposed to the sun for long periods, but it also cannot stay in a hidden place all the time. During the plant's growth period, some thin fertilizer needs to be applied, and fertilizer should be applied frequently to keep the plant supplied with sufficient nutrients. Generally, common fully rotted soybean cake water is sufficient. When the temperature is high, water more, and you can also spray water to increase humidity.
Summary:Miniature bonsai are beautiful and elegant, fashionable and delicate. Whether placed on our office desk or on the desk in our study, they are extremely suitable and extremely beautiful, so interested friends can try looking at miniature bonsai.
Rhododendron rhododendron Rhododendron illustrated guide: How to grow rhododendron / How to propagate rhododendron
Rhododendron profileRhododendron rhododendron
Rhododendron cultivation methods and precautions, introduction to rhododendron
One of China's top ten famous flowers. Among all ornamental flowering trees and shrubs, it can be called beautiful in both flower and leaf, suitable for both ground planting and pot cultivation, and very widely used. Bai Juyi praised it: "Idly break two branches and hold them in hand, looking closely they seem not to exist in the human world; among flowers this thing is Xi Shi, and hibiscus and peony are all Mo Mu." In the natural distribution of rhododendrons in the world, China is famous for having the most species and the largest number of rhododendrons; China is a treasure house of rhododendron resources. Now Jiangxi, Anhui and Guizhou use rhododendron as their provincial flower, and even more cities have designated it as their city flower.
Thorny shrub or small tree, 1-10 m tall, sometimes climbing, much branched, branches stout, young branches sometimes sparsely hairy. Thorns axillary, opposite, stout, 1-5 cm long. Leaves papery or nearly leathery, opposite or clustered on suppressed lateral short branches, obovate or oblong-obovate, rarely ovate to spatulate, 1.8-11.5 cm long, 1-5.7 cm wide, apex obtuse or shortly pointed, base cuneate or decurrent, both surfaces hairless or with strigose hairs, or with sparse stiff hairs along the midvein and lateral veins, vein axils beneath often with short tufted hairs, margin often with short cilia, lateral veins slender, 4-7 pairs, slightly raised beneath, flat above, petiole 2-8 mm long, sparsely pubescent or hairless; stipules membranous, ovate, apex aristate, 3-4 mm long, deciduous.
Flowers solitary or 2-3 clustered at the top of leafy, suppressed lateral short branches, pedicel 2-5 mm long, covered with brownish long soft hairs; calyx tube bell-shaped or ovate, 3.5-7 mm long, 4-5.5 mm wide, outside covered with brownish long soft hairs, limb slightly enlarged, apex 5-lobed, lobes broadly elliptic, apex pointed, 5-8 mm long, 3-6 mm wide, with 3 veins, outside covered with brownish long soft hairs, inside covered with short stiff hairs; corolla initially white, later becoming pale yellow, bell-shaped, outside densely covered with silky hairs, corolla tube relatively broad, about 5 mm long, throat with sparse long soft hairs, corolla lobes 5, ovate or ovate-oblong, 6-10 mm long, about 5.5 mm wide, widely spreading, apex rounded; anthers linear-oblong, exserted, about 3 mm long; ovary 2-locular, each locule with many ovules, style about 4 mm long, stigma spindle-shaped, apex 2-lobed, about 2 mm long. Berry large, spherical, 2-4 cm in diameter, hairless or sparsely pubescent, crowned by persistent calyx lobes, pericarp often thick, seeds numerous. Flowering March-June, fruiting May to January of the following year.
Man shan hong is the leaf of the rhododendron family plant Xing'an rhododendron (Rhododendron dauricum), pungent and bitter in taste, cold in nature, slightly toxic. It enters the lung meridian. It has the effects of relieving cough and eliminating phlegm. It mainly treats acute and chronic bronchitis.
Main components: The leaves contain flavonoids: hyperoside, isohyperoside, farrerol, 8-demethylfarrerol, kaempferol, quercetin, myricetin, azaleatin, dihydroquercetin, gossypetin; coumarins: scopoletin, umbelliferone; phenolic acids: vanillic acid, p-hydroxy-benzoic acid, gallic acid, protocatechuic acid, syringic acid, rhododendrol, etc., as well as hydroquinone and trace andromedotoxin.
It also contains volatile oil, including germacrone, juniper camphor, menthol, α-, β-, and γ-eudesmol and 4-phenyl-butan-2-one. In addition, using gas chromatography-mass spectrometry-computer coupling and chromatographic retention index, two qualitative methods, 24 components were identified from the volatile oil, among which the main components are cis-4,11,11-trimethyl-8-methylenebicyclo[7,2,0]-undeca-4-ene, humulene, γ-selinene, γ-elemene, germacrone and juniper camphor.
Morphological characteristics of rhododendron
The rhododendron genus has many species and varied forms. From large trees (height can reach more than 20 m) to small shrubs (height only 10 cm-20 cm), the trunk is upright or prostrate, and branches are alternate or whorled. It is distributed in Europe, Asia and North America, with the most in Asia. Its difference from Western rhododendron is that its form is relatively shorter and smaller, and its flower type is relatively smaller.
The leaves are mostly rolled back into tube shape, and some are shrunken and broken. After the complete leaf is flattened, it is oblong-elliptic or long obovate, 2-7.5 cm long, 1-3 cm wide, apex obtuse, base nearly rounded or broadly cuneate, margin entire, upper surface dark green to brownish green, scattered with pale yellow glandular scales, lower surface grayish green, with very many glandular scales, midvein raised beneath, lateral veins 4-6 pairs. Petiole 3-10 mm long. Nearly leathery. Odor aromatic and distinctive, taste slightly bitter and slightly pungent.
Ecological habits of rhododendron
In China, it is distributed in all provinces and regions north and south except **, especially with the most species in Yunnan, Tibet and Sichuan, which is the world distribution center of the rhododendron genus. The rhododendron genus has many species and great differences in habits, but most species are produced in high-altitude areas, like cool, humid climates, and hate extreme heat and dryness. They require acidic soil rich in humus, loose, moist and with a pH value between 5.5 and 6.5. Some species and horticultural varieties have strong adaptability, tolerate drought and barrenness, and can also grow in soil with a pH value between 7 and 8. However, on sticky or poorly permeable soil, they grow poorly. Rhododendrons have certain requirements for light, but do not tolerate exposure to the sun. In summer and autumn, there should be deciduous trees or a shade shed to block the scorching sun, and the ground should often be sprayed with water. Rhododendrons generally sprout shoots in spring and autumn, mainly spring shoots. The most suitable growth temperature is 15-20°C; when the temperature exceeds 30°C or falls below 5°C, growth stops. In winter there is a short dormant period, and afterward, as the temperature rises, the flower buds gradually swell. Generally, open-field cultivation blooms from March to May, while in high-altitude areas it blooms as late as July to August. In the north it is cultivated in greenhouses. It can bloom in January to February. Rhododendrons tolerate pruning, and latent buds sprout very easily after being stimulated, which can be used to control tree shape and rejuvenate the tree. Generally, pruning is carried out before May, and the new shoots produced can all form flower buds in the same year; if too late, flowering is affected. Generally, new shoots that sprout around the Beginning of Autumn can still become woody. If new shoots form too late, they are prone to freezing damage in winter. It is an evergreen or deciduous shrub.
Distribution areas of rhododendron
Rhododendron is a large genus, with about 900 species worldwide, distributed in Europe, Asia and North America, mainly produced in East Asia and Southeast Asia, not produced in Africa and South America. There are 850 species, of which China has more than 530 species, accounting for 59% of the world. They are especially concentrated in the Hengduan Mountains area of the three provinces and regions of Yunnan, Tibet and Sichuan, which is the birthplace and distribution center of the world's rhododendrons. In the Himalayan range in Bhutan, Sikkim, Nepal, Myanmar and northern India, there are also relatively many species; in Japan, Korea, Soviet Siberia and the Caucasus there are only a few species.
At the entrance of Longyuan Village, Tangkou Township, Pingnan County, Ningde City, Fujian Province, the tree is more than 3 m tall, with a crown diameter of 5 m, seven branches growing in a cluster, the angular trunk covered with moss, and the tree age is over 400 years. In a year, it has no flowers only in July, and flowers can be seen at other times. The flower color is bright red. According to expert verification, it is a variety of Rhododendron pulchrum and is very precious. Similar rhododendrons have also been found on the mountains at Jiufeng Temple in Xiling Township, Baolin Temple on Tianping Mountain, and Liugongyan Scenic Area.
The ten-thousand-mu rhododendrons on Yunwu Mountain in Huangpi District, Wuhan City have bloomed, and rhododendrons all over the mountains and plains are blooming in brilliant colors. Wuhan City specially launched a Wuhan flower-viewing map for the convenience of tourists. The Fourth Wuhan Mulan Rhododendron Festival was held at the Yunwu Mountain Scenic Area in Huangpi. At the opening ceremony, the Huangpi District Tourism Bureau respectively signed a cooperation agreement with the provincial passenger transport company for the "Wuhan to Mulan Eight Scenic Spots Tourist Direct Bus", signed with Guangzhou for "Ten Thousand Cantonese Visiting Huangpi", and signed with the Huangshi City Tourism Bureau for "Huangshi People Visiting Huangpi". The rhododendrons on Yunwu Mountain are mainly yingshanhong, and there are also 9 varieties including purple-flower rhododendron, jinxiu rhododendron, yunjin rhododendron and red-brown rhododendron. The scenic area chairman introduced that due to differences in altitude, even on the same mountain, the peak blooming period of rhododendrons differs, so the flower-viewing period runs from the end of March to the beginning of May.
At the junction of Qianxi County and Dafang County in western Guizhou, there is a place called "Baili Rhododendron", which is a natural wild rhododendron forest stretching for fifty kilometers, and thus that place is called "the ribbon of the earth, the garden of the world, the hometown of Suoma" (Suoma is the name for rhododendron in the Yi language). The rhododendron species in this rhododendron forest account for 4 of the world's 5 subgenera, and the varieties are also very numerous. The flower area in Dafang County is praised as the "Rhododendron Kingdom" and "Heart of the Sea of Flowers", and Qianxi County is even praised as the "Capital of Rhododendrons". The Baili Rhododendron Management Committee has also increased tourism development efforts, focusing on creating tourism resources combining Yi culture and rhododendron culture, and from the end of March to mid-April each year it attracts many tourists.
Macheng in Hubei has 1 million mu of ancient rhododendrons, including the 100,000 mu of original ecological ancient rhododendron community in the Guifeng Mountain Scenic Area. According to expert verification, its large area, long age, good preservation, high density and beautiful flower color can be called a masterpiece of central China, and it is the largest ancient rhododendron primitive community discovered in China so far. Among them, the "Rhododendron King" on Guifeng Mountain is over 300 years old, with as many as 56 secondary branches, each branch stem between 6 cm and 10 cm, crown diameter reaching 6 m, and coverage area reaching 35 sq m. The ancient rhododendron community on Guifeng Mountain was included in the Shanghai Great World Guinness Records on April 16, 2009, for its large area, long age, high density, good preservation and beautiful flower color.
Rhododendron is produced in Taiwan, China, Guangdong, Hong Kong, China, Macao, China, Guangxi, Hainan, and Menghai, Pu'er, Gengma, Jinghong, Hekou and Simao in Yunnan; it grows in forests or thickets in open fields, hills, mountain slopes, and valley ditches at altitudes of 30-1600 m. Abroad it is distributed in Indonesia, Malaysia, Vietnam, Laos, Cambodia, Thailand, Myanmar, Bangladesh, Nepal, Sikkim, India, Pakistan, Sri Lanka, and the tropical areas of eastern Africa. The type specimen was collected from Macao.
Variety classification of rhododendron
(1) The 5 subgenera of rhododendron: 1. Evergreen scaleless rhododendron subgenus; 2. Evergreen scaly rhododendron subgenus; 3. Chinese azalea subgenus; 4. Yingshanhong subgenus; 5. Mayinhua subgenus.
(2) The 58 subsections of rhododendron:
1. Classification of the evergreen scaleless rhododendron subgenus: the evergreen scaleless rhododendron section is divided into 24 subsections (omitted);
2. Classification of the evergreen scaly rhododendron subgenus: the evergreen scaleless rhododendron section is divided into 27 subsections (omitted), the bearded rhododendron section, and the blueberry rhododendron section divided into 7 subsections (omitted);
3. Classification of the Chinese azalea subgenus: China has only 1 species;
4. Classification of the yingshanhong subgenus: short-calyx section, yingshanhong section;
5. Classification of the mayinhua subgenus: mayinhua section, long-stamen rhododendron section.
Under natural cultivation conditions, the flowering period of spring rhododendrons is mostly April-May; the flowering period of summer rhododendrons is between May and June; the flowering period of spring-summer rhododendrons is between spring and summer rhododendrons; the flowering period can last more than one month.
Species commonly cultivated in China include: mao rhododendron, summer rhododendron, Western rhododendron, east rhododendron, spring rhododendron, Chinese azalea, yinghong rhododendron, mayinhua, and yunyin rhododendron.
The rhododendron genus has about 900 species, with about 850 species produced in Asia. Among them, China has about 530 species, distributed in all north and south subregions except **. New Guinea and Malaysia have about 280 species, almost all epiphytic. In addition, North America has 24 species, Europe has 9 species, and Oceania has 1 species. The rhododendron genus has many species and great differences, including evergreen large trees, small trees, evergreen shrubs and deciduous shrubs.
Rhododendrons are divided into two major categories: deciduous and evergreen. Deciduous types have small leaves, and evergreen types have large leaves. They like cool, humid conditions, tolerate cold, and mostly grow on mountain slopes, alpine meadows, forest edges, rock walls and swamps at altitudes of 1000-1400 m.
Common species
Dabai rhododendron, Daguan rhododendron, Maying rhododendron, Yunnan rhododendron, long-stamen rhododendron, concave-leaf rhododendron, white-flower rhododendron
Guangzhu charming rhododendron, tuanhua rhododendron, many-flower rhododendron, Chinese azalea, Xichang rhododendron, wenke rhododendron, rhododendron
Maying rhododendron, charming rhododendron, fanhua rhododendron, luzhu rhododendron, rusty-leaf rhododendron, Yunnan rhododendron, rhododendron, dabai rhododendron
Rare species
White-flower rhododendron, Chinese azalea, glandular-flower rhododendron
Medicinal or dietary therapeutic value of rhododendron
The medical information and healthy dietary therapy information on Huhua.com is for reference only and cannot be used as a basis for diagnosis or medical treatment. For any health problem, consult professional medical personnel, and for the treatment of any disease, follow doctor's orders.
Ultimate flower-protecting task: love yourself, start from reality, and strictly follow doctor's orders. For illness, do not be careless, do not delay, do not give up hope, face it bravely, use love to warm the silent world, and use your heart to care for the flower field within.
Beauty effects
Rhododendron has antibacterial and anti-inflammatory effects. Among them, syringic acid, vanillic acid and anisic acid all have antibacterial effects and have a good eliminating effect on Cutibacterium acnes caused by acne; the anti-inflammatory effect of its farrerol is equivalent to injected salicylic acid.
Pharmacological effects
1. Antitussive, antiasthmatic and expectorant effects. In mice, po 5 mg germacrone has an antitussive effect equivalent to 2 mg codeine; ip germacrone has the effect of counteracting histamine-induced bronchospasm in guinea pigs. Farrerol is the main effective component of man shan hong in treating bronchitis. Among the effects on individual symptoms, the effective rate for expectorant is the highest, followed by cough relief, and antiasthmatic is poorer. A small amount of ink was injected into the trachea of rabbits, and the movement speed was observed in vivo to determine the speed of tracheal ciliary transport of mucus. After ip farrerol, the transport speed could be significantly accelerated, consistent with the clinical conclusion of expectoration.
2. Anti-inflammatory and antibacterial effects. The guaiazulene contained in this product has anti-inflammatory and uterine-stimulating effects and can be used as an anti-inflammatory agent. Farrerol has antibacterial activity against Staphylococcus aureus, MIC 25 ug/ml. Syringic acid and vanillic acid also have antibacterial and antifungal effects, and anisic acid also has preservative and antibacterial effects.
3. Hypotensive and diuretic effects. Andromedotoxin has a hypotensive effect when given iv to anesthetized cats. Avicularin, although having a hypotensive effect on anesthetized dogs, has a very short duration and easily produces rapid tolerance. Avicularin iv 0.5 mg/kg has a diuretic effect on anesthetized dogs, and the effect increases with dose. In rat experiments, whether po or ip 34 mg/kg can produce a significant diuretic effect; the strength is weaker than aminophylline, but its toxicity is only 1/4 that of aminophylline, so its therapeutic index is relatively large.
4. Analgesic effect. Andromedotoxin has a certain analgesic effect, with a minimum analgesic index of 8.60. Hyoscyamine can greatly strengthen its analgesic effect without a clear effect on toxicity. Atropine can slightly strengthen the analgesic effect of this product. In addition, andromedotoxin has weak cytotoxic activity, with an ED50 of 60 ug/ml, and relatively high in vivo toxicity.
5. Central inhibitory effect. Syringic acid has sedative and local anesthetic effects, and its effects have a dose-dependent relationship.
6. Effect on tissue respiration. Farrerol can inhibit rat trachea-lung tissue respiration in vitro, reducing oxygen consumption by about 26.4%, mainly acting on the pyridine nucleotide enzyme system.
Edible value
Sweet in taste, warm in nature, it can lower blood lipids, lower cholesterol and nourish and beautify the skin. Long-term drinking can make the skin delicate and the complexion rosy; it can lower blood lipids, lower cholesterol, reduce inflammation, nourish and beautify the skin, beautify the skin and harmonize blood, regulate menstruation, dispel wind-dampness, and treat irregular menstruation. It has the effects of clearing heat and detoxifying, beautifying and protecting the skin, harmonizing blood, regulating menstruation, dispelling wind-dampness, and treating rheumatic pain. Azelaic acid can be extracted from rhododendron to make cosmetics, with certain beauty effects. The roots, leaves and flowers of rhododendron are used as medicine and have the effects of harmonizing blood and regulating menstruation, reducing swelling and stopping bleeding; the flowers and leaves used externally on roots can treat internal injuries, rheumatism and other conditions. It can also mainly treat severe wind-phlegm pain, rheumatic arthralgia and wind-worm toothache. Rhododendron has a certain toxicity; please use it under expert guidance.
Cultivation techniques of rhododendron Rhododendron
Also known as yingshanhong, it generally refers to various red rhododendrons, describing its vivid red brilliance like blazing fire that reddens the mountains. In fact, rhododendron is not only red. In today's plant taxonomy, "yingshanhong" is only regarded as one species (including many cultivated varieties). Yunnan Province alone and Macheng City in Hubei have nearly 300 species. China is the native place of rhododendrons, and Macheng is also its distribution center.
Yingshanhong
It is a common type of rhododendron, named because when its flowers bloom they redden the whole mountain. In Longlin, Macheng City, Hubei Province, and in mountainous areas at altitudes of more than 500 m such as Xijiang, Fenghuang Mountain, Zhuangkou and Lanshan in Huichang County, Ganzhou City, Jiangxi Province, it is distributed. Yingshanhong has long had the reputation of "king of woody flowers". Writers and poets ancient and modern, Chinese and foreign, have written many beautiful essays and poems praising yingshanhong, such as one by Yang Wanli of the Song Dynasty: "Why must one look at the spring breeze in famous gardens; along the way the mountain flowers do not fail you. Day after day the Jin River presents a brocade-like scene, and the clear stream reflects yingshanhong upside down." This praises the plain and tenacious vitality of yingshanhong.
Wild rhododendrons are mostly shrubs and small trees 1-2 m tall. There are also the creeping rhododendron and purple-back rhododendron only a few centimeters tall and prostrate on rocky ground, as well as the big-tree rhododendron and giant rhododendron reaching several zhang tall and bearing ten thousand flowers. The top of the rhododendron forms an umbel-like inflorescence, composed of several bell-shaped or funnel-shaped flowers, just like a full hydrangea. The leaves are mostly leathery, as large as loquat and as small as a fingernail. There is even a species called tujian rhododendron whose leaves are as long as more than 70 cm and more than 20 cm wide; the fruit is a capsule, and the seeds are as fine as dust, so sowing must be carefully managed before they can emerge and become seedlings.
In Yunnan, rhododendrons grow in high mountains, middle mountains, low hills and fields at altitudes of 800-4500 m, with the richest species in the high mountains of western Yunnan. This is especially true in high-altitude cold and humid zones. Many evergreen rhododendrons such as yellow-cup rhododendron, white-snow rhododendron, tuanhua rhododendron and broad-bell rhododendron, in various colors, often form dense rhododendron thickets and pure forests, and there is even the spectacle of continuous "seas of flowers" of rhododendrons stretching for ten to twenty kilometers. The flowering period of rhododendrons differs according to climate and species. In low mountain warm and hot zones they mostly open in February-March, in middle mountain cool zones they mostly open in April-June, and in high mountain cold and cool zones they mostly open in July-August. Because of their many species, wide distribution and complex and diverse ecological environments, the postures of rhododendrons are also diverse: some have sparse branches and leaves, some have a hundred dry branches; some are lush and upright, some are curved like dragons and vigorous and antique. Their flower colors are even more colorful and varied: deep red like fire, golden brilliant, crystal blue like treasure, or with spots and dots, or with stripes and patches, pink, carmine, orange-yellow, light purple, red within yellow, white within red, green within white, truly ever-changing and full of wonders. Some are heavily made up and brightly dressed, some are plainly clothed in white, some have red lips and white teeth, some are fragrant and refreshing, truly each with its own style and a thousand postures.
Precisely because of the important value of rhododendrons in landscaping, China's richly varied rhododendron resources were long coveted by Western countries. As early as the beginning of the 19th century, they sent people to Yunnan many times at great expense to collect specimens and seeds. The several hundred rhododendrons that the Royal Botanic Gardens in England now boasts of were mostly collected and cultivated from Yunnan, and have long since become forests. When the flower buds are in full bloom, English men and women come and go in streams, lingering and forgetting to return.
Flowering period control
If you want flowers during the Spring Festival, you can move the potted flower to a sunny spot in a 20°C greenhouse in January or 20 days before the Spring Festival, with other management as normal, and you can view the flowers during the Spring Festival. If you want flowers for "May Day", you can move the pot to an indoor cold storage below 5°C before budding in early spring, move it to a sunny spot in a 20°C greenhouse on April 10, and move it outdoors on April 20, and you can see flowers for "May Day". Therefore, temperature can regulate the flowering period, allowing it to open at will and in all four seasons. In addition, plants pruned immediately after flowering can bloom in late October; if pruned during the peak growth season, the flowering period can be delayed by about 40 days; if pruning is combined with cuttings, the flowering period can be delayed to January-February of the following year. Therefore, pruning at different times also affects how early or late the flowering period is.
Fertilization techniques
When fertilizing flowers, you must grasp the season and achieve timely, appropriate amount and properly configured concentration. The root system of rhododendrons is very fine and dense, with strong ability to absorb water and fertilizer; they like fertilizer but fear concentrated fertilizer. Generally, human feces and urine are not suitable; it is appropriate to apply alum fertilizer water as a top dressing.
Fertilization of rhododendrons should also be carried out according to different growth periods. From March to May, to promote the growth of branches, leaves and flower buds, fertilize once a week. June to August is midsummer, when rhododendron growth gradually slows and enters a semi-dormant state. Too much fertilizer will not only cause old leaves to fall and new leaves to turn yellow, but also make it prone to pests and diseases, so fertilization should be stopped. In late September the weather gradually turns cool, and rhododendrons enter autumn growth. Apply a 20%-30% phosphorus-containing liquid fertilizer once every 10 days to promote the growth of flower buds. Generally after October, autumn growth basically stops, so no more fertilizing is done.
Care key points 1. Environmental conditions
Humidity, acidic soil and warmth are the environment rhododendrons like most; exposure to the sun, drought and waterlogging, and concentrated fertilizer are the growth environment rhododendrons fear most. For soil culture, rhododendron soil must be acidic soil with good aeration, rich humus and a pH value of 5.5-6.5. To maintain the acidity of the rhododendron potting soil, usually apply some alum fertilizer water appropriately, or add a little ferrous sulfate to the water when applying. When repotting rhododendrons, add an appropriate amount of slow-release fertilizer to the potting soil. This fertilizer is often used in rhododendron horticultural production; it is both convenient and clean, so planted rhododendrons also have lush leaves and brilliant flowers.
2. Potting soil requirements
Rhododendrons like loose, highly permeable, well-drained acidic soil rich in humus, with a pH value of 5.0-6.0. If clay or alkaline soil is used, hardly one in a hundred survives. In particular, summer rhododendrons and Western rhododendrons must have mountain soil. Mountain soil also needs to be improved. Generally, 3 prepared culture soils are used.
(1) Mix 7 parts mountain soil, 1 part dry moss grass debris, 2 parts dry leaf mold, and 1 part dry fertilizer.
(2) Layer and compost 3 parts mountain surface soil (topsoil), 3 parts horse manure, 3 parts fallen leaves and weeds, and 1 part human feces and urine, and after 1-2 years sieve for later use.
(3) Mix 3 parts mountain soil, 3 parts leaf mold, 4 parts garden soil and 2 parts sandy soil, and add 50 grams of sesame paste residue and bone meal to each pot.
3. Flower pot selection
For flower pots for cultivating rhododendrons, depending on the use, generally two kinds are chosen: clay pots and purple clay pots. Clay pots have good air and water permeability, which is beneficial to root growth; flower and tree production units all use this pot for cultivation. Finished rhododendrons, especially already styled rhododendrons, for indoor and outdoor display, are generally planted in beautiful and antique purple clay pots. Purple clay pots have fine texture, rich colors and beautiful shapes, and can increase ornamental value. Purple clay pots are not as permeable as clay pots, so when planting, broken tile pieces (old tiles) should be placed around the pot walls to facilitate drainage. The size of the selected pot depends on the plant's age. Generally, 4-6 year old plants use 5-inch pots; 7-10 year old plants use 6-inch pots; 11-15 year old plants use 8-inch pots.
4. Improving water quality
For watering rhododendrons, it is best to use rainwater, followed by river water and pond water. If tap water is used, it is best to store the water for 1-2 days to let the chlorine volatilize before use. When using it, add 0.2% ferrous sulfate and water once every 7-10 days during the growing season. Regular use ensures the soil is acidic.
5. Fertilizer and water management
Rhododendrons like shade and moisture and should not be too dry. During the flowering period, even more water is needed. In winter, rhododendrons have entered the dormant period and do not need much water. Generally, water once every 4-5 days, preferably around noon on clear and warm days. Specifically, water appropriately depending on the dryness of the potting soil. In March, rhododendrons take root and sprout, and water demand increases accordingly. Summer rhododendrons grow and develop slightly later, and the amount of watering should be less than for spring rhododendrons. Generally, water appropriately once every 2 days in the morning. From April to June, rhododendrons bloom one after another and branches and leaves also begin to sprout, requiring a relatively large amount of water. Generally, water once every morning or evening. In the high-temperature and dry season from July to early September, water once in the morning and once in the evening, and the amount should not be too much, and spray water on the leaves and ground at noon to maintain a humid environment. From mid-September to November, the weather gradually turns cool, which is the adaptation period for rhododendron growth. To prevent autumn shoots from sprouting and enhance overwintering cold resistance, the amount of watering should be appropriately reduced. Generally, water once every other day in the early morning, keeping it moist. Rhododendrons relatively like fertilizer. Generally, rotted cake fertilizer, fish meal, broad bean or Chinese milk vetch, etc., after rotting, are mixed with water and used for irrigation. Human feces and urine are taboo. After leaving the house and before the flower buds spit out flowers, apply thin fertilizer once every 10 days at a concentration of 15%, for a total of 2-3 times, to promote old leaves turning green and new roots sprouting. After the flowers fade, in order to promote branch and leaf growth, fertilize 5-6 times from mid-May to early July. If it rains continuously, dry fertilizer can be applied. Before entering the house, when rhododendron growth is about to stop, fertilize 1-2 times.
6. Outdoor shading
Before leaving the house and before flowering, it is appropriate to see more sunlight; during the flowering period, short-term shading should be carried out at noon, with a light transmittance of 60%; during the plum rain period from June to early July, which is exactly the period when rhododendrons sprout leaves and branches, they should see as much sunlight as possible. But when encountering strong sunlight, shading should still be carried out from 9 a.m. to 4 p.m. to prevent burning new leaves. From mid-July to early September, shade from 8 a.m. to 5 p.m. every day to prevent scorching sunlight. After September, in the autumn growth period, the shading time can be shortened. Generally, shade from 10 a.m. to 4 p.m., and after October it is appropriate to see more sunlight. Then carry out shaping, cutting off leggy branches, diseased and weak branches, deformed branches and damaged branches.
7. Shaping and pruning
Rhododendrons grow relatively slowly. Generally, let them grow naturally, and only carry out shaping after flowering, cutting off leggy branches, diseased and weak branches, deformed branches and damaged branches.
8. Cutting propagation
Rhododendrons can be propagated by five methods: cuttings, grafting, layering, division and sowing. Among them, cutting is the most common and produces the largest number of propagules; layering produces seedlings fastest, grafting propagation is the most complex, and grafting is used only for varieties that are difficult to root by cutting; sowing is mainly used for breeding varieties.
For cutting propagation, the cutting pot is preferably a new shallow clay pot with a 20 cm diameter, because it has good air permeability and is easy to root. A culture soil mixed with 20% humus garden soil, 40% horse manure debris and 40% river sand can be used as the substrate. The best time for cuttings is spring (May) and autumn (October), when the temperature is between 20-25°C, most suitable for cuttings. When taking cuttings, choose healthy, vigorously developing current-year semi-lignified branch tips as cuttings, use very sharp pruning shears, cut 6-10 cm with nodes, and the cut must be smooth and neat. Remove the lower leaves and keep only 3-4 small leaves at the top. Buy 1 ampoule of vitamin B12 injection, open it, dip the cutting in the liquid medicine, take it out and let it dry for a while, then it can be inserted. Before inserting, the culture soil in the pot should be sprayed moist with a watering can the day before, but not too much; by the next day it is just moist, most suitable for cuttings. The insertion depth is 3-4 cm. When inserting, first use chopsticks to poke a hole in the soil, then insert the cutting, press the soil firmly with your hand so that the potting soil and the cutting are fully in contact, then water thoroughly once. After inserting, the flower pot is best covered with a plastic bag, and the bag opening tied with a string. Open it when watering is needed, and tie it again after watering. The pot that has been used for cuttings should be placed in a place without direct sunlight. The potting soil of the cuttings should be sprayed with water every day for 10 days. Except on rainy days, spray once on cloudy days, and twice when the climate is dry, but the amount of water sprayed each day should not be too much. After 10 days, still frequently pay attention to keeping the soil moist. Within 4-5 weeks, shade is required, and only after sprouting can it gradually receive some sunlight. Generally, it takes about 2 months to root. After that, it only needs shading for 2-3 hours at noon, and the rest of the time it can receive light as it pleases, so as to facilitate photosynthesis and manufacture nutrients on its own.
9. Garden uses
Rhododendrons have abundant flowers and lush leaves, are beautiful and varied, have strong sprouting ability, tolerate pruning, and have peculiar root stumps, making them excellent bonsai material. In gardens, they are most suitable for planting in clusters along forest edges, streamsides, pond banks and beside rocks, and can also be scattered under open forests.
10. Light and temperature
During the period when rhododendrons sprout leaves and branches, they should see as much sunlight as possible, but when encountering strong sunlight, shading should still be carried out from 9 a.m. to 4 p.m. to prevent burning new leaves. In summer, shade from 8 a.m. to 5 p.m. every day; after September the shading time can be shortened; after October it is appropriate to see more sunlight.
Rhododendrons grow most vigorously at around 20°C and stop growing and enter a dormant state above 30°C. Long-term exposure below 0°C will freeze them to death. In winter, heat preservation measures must be taken, and a temperature above 15°C is best.
Disease and pest control of rhododendron
Disease and pest prevention and control: For the azalea lace bug (also known as the pear lace bug), spray 40% dimethoate 1500 times solution during the damage period, once every 7 days, for 3 consecutive times. The control method for the terminal bud leaf roller is mainly manual capture and killing; larvae or pupae can also be sprayed and killed with 40% dimethoate emulsifiable concentrate 2000 times solution or dichlorvos 1500 times solution.
For red spider mite, 1000 times dicofol solution can be used for control. For the azalea lace bug, 1500 times dimethoate or dichlorvos can be used for control. The most common disease is brown spot, which can be controlled with 800 times thiophanate or equal-strength Bordeaux mixture.
Main pests and diseases
Red spider mite. It can be sprayed and killed with 40% dimethoate 1500-2000 times solution, 58% Fenglei Ji emulsifiable concentrate 1500-2500 times solution, etc.
Azalea lace bug (pear lace bug). It can be sprayed and killed with 50% fenitrothion 1000 times solution.
Tea bagworm (bagworm, case moth). It can be killed by spraying with 90% trichlorfon at 2000 times dilution.
Tea tortrix (leaf-tying caterpillar). Adults can be trapped and killed with black light lamps, and larvae can be killed by spraying with 20% diflubenzuron suspension concentrate at 8000 times dilution, 20% dichlorvos at 2000 times dilution, etc.
Damping-off. It mostly occurs on seedbeds. When it causes damage, it turns the seedlings from the roots to the root crown brown, and later dark brown. In severe cases, the phloem rots, the xylem is exposed, and the roots rot and turn blackish brown, causing the aboveground leaves of the seedlings to wither and yellow or even the whole plant to die, but without lodging. The occurrence of this disease is mostly caused by planting seedlings too densely, poor ventilation, or an overly wet seedbed. To prevent and control this disease, the seedbed must first be well ventilated and exposed to light, and shading work should be done well in high-temperature seasons; at the same time, be careful not to water too much and make the soil too wet. If the seedbed soil is first disinfected with 50% captan at 500 times dilution, the effect is even better.
Leaf spot disease. Leaf spot disease of rhododendrons is a common disease. In the early stage of damage, small purplish-red spots appear on the leaves, and later the center of the diseased spot becomes grayish white. Small black dots grow on it and cause the leaves to fall off. This disease occurs 3 times a year on Western azaleas, with mid-month, early September, and early October being peak periods of occurrence. In winter, after Western azaleas are moved indoors for maintenance, it will continue to occur as long as the temperature is suitable. Overall, leaf spot disease is severe during the plum rain and tropical storm seasons. If 70% thiophanate-methyl at 1 times dilution, or 20% triadimefon at 4000 times dilution, or 50% mancozeb at 500 times dilution can be sprayed once every 2 weeks from May to late August after flowering, the development of this disease can be controlled.
Chlorosis. Chlorosis of rhododendrons often causes their green leaves to evenly lose green color, and the leaf color becomes lighter. First, the young leaves lose green, and the leaf mesophyll turns yellow. In severe cases, the leaves turn white, the leaf veins also turn yellow, and necrotic tissues such as scorched brown spots appear in the middle of both sides of the leaf or at the leaf tip, gradually expanding and causing the leaves to fall off. The occurrence of this disease is mainly caused by iron deficiency due to alkaline soil. When this symptom appears, spraying the plant with 0.2%-0.5% ferrous sulfate solution in time is more effective than directly applying it to the soil.
Geometrid. Adults can be trapped and killed with black light lamps, and larvae can be killed by spraying with 20% fenvalerate-cypermethrin emulsifiable concentrate at 2000 times dilution, 25% fengmang emulsifiable concentrate at 800-1000 times dilution, etc.
Brown spot disease. It can be sprayed with 70% thiophanate-methyl at 1000 times dilution, 65% zineb at 600-800 times dilution, etc., once every 5-7 days. Spray 3-5 times continuously depending on the condition.
Root rot. Pay attention to strengthening cultivation management, keep the soil moist and loose, and avoid water accumulation. In the early stage of the disease, irrigate the roots with 12% copper green emulsifiable concentrate at 800-1000 times dilution or Lüheng No. 1 at 3000 times dilution, once a week, for 2-3 consecutive times. When the disease is severe, the plant should be dug out of the soil in time (potted plants or bonsai should be repotted and the soil changed in time), wash off the soil from the roots, cut off the diseased root system, then soak the plant roots for 30 minutes with 12% copper rosinate emulsifiable concentrate at 600 times dilution, or Lüheng No. 2 at 800 times dilution, or 50% root rot spirit wettable powder at 500 times dilution, then rinse the roots with clean water, then use 75% chlorothalonil wettable powder at 1000 times dilution, or 50% carbendazim wettable powder at 800 times dilution, add an appropriate amount of fine red (yellow) soil, stir into a thick mud slurry, and dip the roots before planting. For field planting, new holes should be dug and the soil loosened (for potted plants and bonsai, loose new culture soil should be used), and 50% root rot spirit at 600 times dilution or 50% fungicide king water-soluble powder at 1000 times dilution, Lüheng No. 1 at 3000 times dilution, 12% copper green emulsifiable concentrate at 600 times dilution, etc., should be used to irrigate the soil (culture soil) for disinfection, and then the plant should be planted. After planting, spray the leaves once a week with 12% copper rosinate emulsifiable concentrate at 1000 times dilution or 50% root rot spirit wettable powder at 800 times dilution, Lüheng No. 2 at 600-800 times dilution, 70% manganese fungicide wettable powder at 600-800 times dilution and other fungicides. It is best to use two or more alternately, and spray 3-5 times continuously.
Leaf gall disease (pie disease). Strengthen cultivation management, pay attention to environmental ventilation and light transmission, promptly and thoroughly remove diseased leaves and diseased shoots when found, and destroy them in time. Before germination in spring, spray the plant once with 1 degree Baume lime sulfur mixture. During the new leaf development period, spray the leaf surface 2-3 times with 0.5 degree Baume lime sulfur mixture or 1% Bordeaux mixture, once every 7-10 days.[3]
Split-belly disease
[Symptoms] The phloem of the lower stem of the rhododendron is damaged and necrotic, the xylem is exposed, and small black dots are produced on the diseased part.
[Pathogen] The pathogen is a fungus, wheat leptosphaeria (Leptosphaeria tritici).
[Occurrence pattern] It generally occurs during the plum rain season. Any factor causing stem injury will aggravate the disease, such as insect injury, mechanical injury, friction injury, etc.
[Control method] Spray with 50% carbendazim at 500 times dilution, once every 10-15 days. After spraying 2-3 times continuously, the condition can be controlled.
The flower language of rhododendron
The flower language of rhododendron - always belong to you
The flower language of rhododendron - represents the joy of love. It is said that people who like this flower are pure and innocent. The motto of rhododendron is that when rhododendrons bloom all over the mountains, it is the time when the god of love descends.
Flower language: joy of love, moderation, moderating desire
Flower color meaning: joy of love
White: the joy of being loved
Its flower language is "moderation." The biggest reason is that it blooms only in its own flowering season, even though rhododendrons always give people a lively and noisy feeling. When it is not in flowering season, its dark green leaves are also very suitable for planting in gardens as low walls or barriers.
The cultural background of rhododendron
In 492 AD, Tao Hongjing of the Qi and Liang dynasties recorded in Collected Commentaries on the Classic of Materia Medica: "Yang zhizhu, if a sheep eats its leaves, it will pace back and forth and die, hence the name."
Su Shi of the Northern Song Dynasty also mentioned it many times in his poems, "At that time I only thought it was the immortal of Helin, able to leave autumn light and let rhododendrons bloom." In addition, Bai Juyi of the Tang Dynasty also wrote "Delight at Mountain Pomegranate Flowers Blooming": "Today's flowers in Zhongzhou, last year's trees on the top of Mount Lu. I have already pitied the roots being damaged and cut for new planting, and I am still delighted that the flowers bloom in the same number as before."
Li Shizhen of the Ming Dynasty recorded Yang zhizhu and Yingshanhong in more detail in Compendium of Materia Medica. Slightly later, the famous geographer Xu Hongzu wrote The Travels of Xu Xiake, which described the rhododendrons of central Yunnan.
Rhododendron pictures