Can Calliandra be grown indoors? Detailed care guide

Calliandra loves light, so at home it is best placed on a balcony with plenty of sunlight. How to grow Calliandra? Can it be kept indoors:

How to grow Calliandra:

1. Potting: For home potting, choose garden soil mixed with some river sand as the potting medium, and place it on a south-facing balcony for growing and viewing. The optimum growth temperature is 23°C to 30°C; during winter keep the temperature at 15°C to 18°C and shelter it from wind, which can reduce leaf drop.

Normally, water when the top 1 cm of the potting soil is dry; in winter, water when half of the potting soil is dry. Apply a compound fertilizer once a month from spring to autumn.

2. Water and fertilizer: Young Calliandra plants need more water, so pay attention to irrigation during the growing season. Potted plants are more prone to drought and water shortage, with leaves showing a wilting appearance, so attention should be paid to replenishing water. How to grow Calliandra_ Calliandra cultivation methods How to grow Calliandra Calliandra cultivation methods.

For fertilization, natural organic fertilizer or compound fertilizer can be used, applied once a month; during the flowering period, apply more phosphorus and potassium fertilizer. The cultivation site needs sufficient sunlight; in shaded places flowering is poor.

Can Calliandra be kept indoors:

Calliandra is suitable for home growing, but it is best not to place it indoors. Calliandra's appearance is very cute; its red flower filaments are like down, giving a constantly cute impression.

However, considering Calliandra's growth habits. Because it has high requirements for light and temperature, it is best not to place it indoors for care; it can be placed on a balcony or windowsill and other such places.

You can rest assured, Calliandra is not toxic, so it can be grown with peace of mind.

Peony Paeonia lactiflora Peony illustrated guide: How to grow peony / How to propagate peony

Introduction to the Rhododendron

  Rhododendron -- the Western Beauty among flowers, scientific name Rhododendron simsii & R.spp. Also known as yingshanhong, shanshiliu, shanzhizhu, hongzhizhu, shanjuan, etc. Family and genus: Ericaceae, Rhododendron genus. The rhododendron is one of China's top ten famous flowers.

  Among all ornamental flowering trees and shrubs, the one that can be called beautiful in both flower and leaf, suitable for both ground planting and pot culture, and most widely used, must be the rhododendron. In the natural distribution of rhododendrons in the world, none can match China in the number of species and the vastness of quantity; China is a treasure house of the world's rhododendron resources! The rhododendron is a large genus, with about 900 or more species worldwide, distributed in Europe, Asia and North America, with the most in Asia, 850 species, of which China has 530 or more species, accounting for 59% of the world's species, especially concentrated in the Hengduan Mountains area of the three provinces and regions of Yunnan, Tibet and Sichuan, which is the world's birthplace and distribution center of rhododendrons.

  In different natural environments, rhododendrons form different morphological characteristics, with extremely great differences: there are evergreen large trees, small trees, evergreen shrubs, deciduous shrubs; some have thick, large trunks reaching more than 20 m tall, and some are prostrate, cushion-like or epiphytic types, only 10-20 cm tall.

  The basic form is: trunk erect, solitary or clustered; branches alternate or falsely whorled. Branches and leaves hairy or not; branches, leaves and pedicels scaly or not; leaves varied in shape, but not linear, entire, rarely finely serrate, leathery or papery, evergreen, semi-evergreen or deciduous, fragrant or not; flowers terminal, lateral or axillary, single-flowered, few-flowered or more than 20 gathered into racemose umbels, flowering before the leaves or after them, corolla conspicuous, funnel-shaped, bell-shaped, radiate salverform bell-shaped, dish-shaped to bowl-shaped or tubular, 4-5 lobed, also 6-10 lobed; flower colors rich and varied; throat with dark spots or light-colored halo; base with nectary or not; fragrant or odorless; calyx cup-shaped, 4-5 lobed, persistent; stamens 5-10, rarely 10-25, unequal in length, filaments hairy or not, dorsifixed anthers, dehiscing by apical pores, ovary superior, 5-10 locular, style and ovary hairy or not, glandular or not; capsule dehiscing into 5-10 valves, seeds numerous, mostly powdery or chaff-like.

  Classification of original species. The whole genus is divided into 5 subgenera and 8 sections, of which 3 sections are further divided into 58 subsections, and beneath the sections are species. Namely:

  I. Subgenus Evergreen Scaly-less Rhododendron: 1. Section Evergreen Scaly-less Rhododendron, below which are divided 24 subsections.

  II. Subgenus Evergreen Scaly Rhododendron: 1. Section Evergreen Scaly Rhododendron, below which are divided 27 subsections. 2. Section Beard-flowered Rhododendron 3. Section Bilberry Rhododendron, below which are divided 7 subsections.

  III. Subgenus Sheep Azalea, China has only 1 species.

  IV. Subgenus Yingshanhong, 1. Section Short-calyx 2. Section Yingshanhong

  V. Subgenus Horse-silver-flower, 1. Section Horse-silver-flower 2. Section Long-stamened Rhododendron

  The above three subgenera I, II and V are customarily called evergreen rhododendrons, and the two subgenera III and IV are called deciduous rhododendrons.

  Now several kinds of evergreen rhododendrons are introduced below:

  Rhododendron delavayi: also known as mayinghua, mabiyang, niuxuehua, gouxuehua, hongshanchai, mitonghua. Evergreen shrub to tree, tree height 2-15 m, diameter at breast height up to 40 cm, bark grayish brown, thick, peeling in irregular flakes. Leaves leathery, oblong-lanceolate, the underside densely covered with grayish white to light brown spongy thin woolly hairs. Flowering February to May, terminal spherical umbels, with 10-20 flowers, corolla bell-shaped, 3.5-5 cm long, fleshy, deep rose red, stamens 10, ovary 10-locular. Fruit ripens October to November. Produced in Yunnan, Guizhou, Guangxi and other provinces and regions, also distributed in Myanmar.

  Rhododendron fortunei: also known as Tianmu rhododendron, yunjinhua. Evergreen shrub, 2-4 m tall, branchlets sturdy, pale green. Leaves thickly leathery, oblong to oblong-elliptic or obovate, upper surface dark green, underside pale green, hairless. Flowering May, terminal racemose umbels, with 6-12 flowers, fragrant, corolla funnel-shaped bell-shaped, 4-5 cm long, 7-9 cm in diameter, pale pink, 7 lobes, rounded, stamens 14, ovary 10-locular, pedicels, calyx, base of corolla, ovary and style all glandular. Fruit ripens October to November. Seeds numerous, chaff-like. Produced in mountain forests at 600-2000 m elevation in Zhejiang, Anhui, Jiangxi, Fujian, Guangdong, Guangxi, Hunan, Sichuan and other places; in recent years Hangzhou, Wuxi, Shanghai and other places have successfully introduced it into garden planting.

  Rhododendron giganteum: also known as dashangouquanhua. Evergreen large tree, up to 25 m tall, diameter at breast height 60-*0 cm, the largest basal diameter reaching 3 m. Bark pale dark brown, peeling in flakes; branchlets sturdy, covered with pale gray felted hairs. Leaves leathery, oblong to oblanceolate, 24-34 cm long, apex obtuse, base broadly cuneate, upper surface dark green, underside pale green. In February to March it puts out terminal racemose umbels, with 24 flowers, corolla bell-shaped, 5.5-8 cm long, 6-8 cm in diameter, water-red, 8 lobes, rounded, base with 8 nectary sacs, stamens 16, ovary 16-locular, densely covered with woolly hairs. Fruiting period October to November. Produced in the mountain evergreen broad-leaved monsoon rainforest at 2400-**** m elevation on Gaoligong Mountain in Tengchong County, Yunnan; in 1915 the Englishman G. Forrest first collected it at Hetou in Tengchong, sawed off a wood disc 2.6 m in circumference and 280 years in annual rings, now kept in the British Museum in London, and published it as a new species in 1926; it was long unfound in China until 1983 when Professor Feng Guolv and others rediscovered it in Tengchong, and the following year found a large tree with a basal diameter of 3.07 m. This is the tallest rhododendron tree in the world, known as the "king of rhododendrons."

  Rhododendron ovatum: also known as ovate-leaved rhododendron, qingminghua. Evergreen shrub, 2-4 m tall. Leaves leathery, broadly ovate, 3-3.5 cm long, apex acute to obtuse, with a protruding tip, base rounded. Flowering March to May, flowers solitary in leaf axils, pink, rose red, pale purple or purple-white, 5-lobed, 3 cm in diameter, throat with soft hairs, stamens 5, ovary 5-locular. Fruiting period August to October. Produced in hillside shady sparse forests or ravine thickets at 500-1200 m elevation in Jiangsu, Zhejiang, Anhui, Jiangxi, Hubei, Hunan, Fujian, Guangdong, Guangxi, Sichuan, Guizhou and other provinces and regions. Horticultural varieties: at present about two to three hundred horticultural varieties are widely cultivated in China; because their main bloodline is yingshanhong, although they do not shed leaves in winter, they are still classified as deciduous rhododendrons. Now, according to morphology, traits, parentage and origin, they are divided into 4 types: East Azalea, Hairy Azalea, West Azalea, Summer Azalea.

  East Azalea: namely the Oriental azalea, because it comes from Japan. Also called shiyan, cinnabar rhododendron, spring azalea small-flowered type, etc. This category includes Rhododendron obtusum and its varieties, with very many cultivars. Its main features: small stature, 1-2 m tall, branches loose and scattered, leaves thin and pale, hairs few and somewhat glossy, blooming in April, flowers dense, the smallest flowers, generally 2-4 cm in diameter, at most 6 cm, single or hose-in-hose formed by calyx petalization, rarely double, flower colors various. Traditional cultivars include 'Xintiandi', 'Xueyue', 'Bizhi', 'Rizhichu', and 'Sijizhiyu' which can bloom twice in spring and autumn, etc.

  Hairy Azalea: commonly known as hairy-leaved rhododendron, large-leaved rhododendron, spring azalea large-leaved type, etc. This category includes Rhododendron pulchrum, Rhododendron mucronatum and their varieties and hybrids, tall in stature, reaching 2-3 m, robust in growth, strong in adaptability, can be planted in the open, and is an excellent rootstock for grafting West Azaleas. Young branches densely covered with brown bristles. Leaves up to 10 cm long, rough and hairy. Flowers large, single, broadly funnel-shaped, rarely double, flower colors red, purple, pink, white and blended, etc. There are more than 10 cultivars, the most cultivated being 'Yuhudie', 'Zihudie', 'Liuqiuhong', 'Yuling', etc.

  West Azalea: first bred in the Netherlands and Belgium in Western Europe, hence called Western azalea, abbreviated West Azalea; it is formed by complex repeated crossing of Rhododendron indicum, yingshanhong and Rhododendron mucronatum, etc., and is the type with the most and most beautiful flower colors and flower forms. Its main features are short and sturdy stature, compact crown, delicate habits, fearing sun and cold. Leaves thick, dark green, few hairs, leaf shapes divided into glossy-leaf, pointed-leaf, twisted-leaf, long-leaf and broad-leaf. Flowering April to May, flower colors diverse, including solid color, feibai, edged, dotted red, bright blotches, sprayed sand, sprinkled brocade, etc., most being double or semi-double, rarely single; petals have narrow-long, rounded, flat, back-turned, wavy, flying, crinkled-edge, rolled-edge, etc., 6-8 cm in diameter, the largest can exceed 10 cm; traditional cultivars include 'Huangquan', 'Jinpao', 'Tiannvwu', 'SihaiBo', etc., and in recent years a large number of new hybrid cultivars have appeared.

  Summer Azalea: native to India and Japan, called gaoyue rhododendron in Japan. It sends out branches first and blooms latest, generally from late May to June, hence the name. Main features are slender branches and leaves, dense branching, full and neat crown, about 1 m tall. Leaves narrow and small, closely arranged. Flowers broadly funnel-shaped, 6-8 cm in diameter, flower colors and petals as rich and varied as the West Azalea; flowers single, semi-double, double; it is a good material for making bonsai. Traditional cultivars include 'Changhua', 'Dahongpao', 'Chenjiayinhong', 'Wubaolvzhu', 'Zichendian', etc. Among them, 'Wubaolvzhu' has a small flower within the flower, in a terrace-like form, and is the most double-flowered of the rhododendrons.

  The main producing areas of rhododendrons in China are the Hengduan Mountains of the three provinces and regions of Yunnan, Tibet and Sichuan; their intricate terrain and topography form a special climate, with extremely uneven rainfall distribution, dry winter and spring, rainy summer and autumn, and obvious vertical distribution.

  In the low flat valleys at 1000-2000 m, there are pointed-leaved rhododendron, giant rhododendron, etc. At 2000-2800 m, the climate is cool, with bright-haired rhododendron, thick-stalked rhododendron, Yunnan rhododendron, axillary-flowered rhododendron, etc. At 2800-**** m in ravine sunny slopes, there are mixed forests of evergreen broad-leaved and deciduous broad-leaved trees; at their forest edges or grassy slopes, yellow-cup rhododendron, white-snow rhododendron, clustered-flowered rhododendron, hairy-throated rhododendron, grassland rhododendron, etc. form impenetrable rhododendron forests or thickets; here the rhododendron species are most numerous, flowering April to July, in five colors and six hues, brilliant as brocade, sometimes covering an entire hilltop for ten to twenty sq km. In the 4000-**** m zone, trees and shrubs are few, and the 10-20 cm tall multi-branched rhododendron, prostrate rhododendron, golden rhododendron, etc. become cushion plants, multiplying on gravelly graves or scree slopes. Above 4500 m there is no rhododendron distribution. Alpine evergreen rhododendrons have long grown in moist, cold high-altitude mountain areas; introduction must create similar environmental conditions, such as no water accumulation on the ground, soil pH 5-6, good permeability, rich in organic matter, and equipment for shading, spraying water and cooling.

  Yingshanhong is the representative of deciduous rhododendrons, the most widely distributed, north to Henan and Shandong, south to the Pearl River basin, east to Fujian and Taiwan, China, west to Sichuan, Yunnan and Guizhou; in high mountains, low hills, shady and sunny slopes, stream valleys and mountain rocks, in forests and forest edges, in wild grass and thickets, it is found everywhere. In Jiangnan it blooms in March to April, a brilliant red expanse. Mountain villagers use it as firewood, and it sprouts again and again after repeated cutting, showing how strong its adaptability and vitality are. In the past, transplanting it was hard to keep alive, which was related to not having pruned it heavily. Although horticultural varieties have been improved by humans, they still reflect the basic habits of the original species: cold-tolerant and heat-fearing, and they require fertile acidic, loose and permeable soil. Some rhododendrons live very long, such as the large tree rhododendron over 500 years old in Yunnan, and the Rhododendron pulchrum planted in the open for over 50 years in Wuxi.

  Rhododendrons set seed abundantly, have many seeds and a high germination rate; saving seeds can obtain a large number of offspring, and the seedlings' plasticity and vitality are strong, making it an important means of introduction and breeding.

  (1) Seed collection: in autumn, when the capsules turn green-brown or yellow-brown, they can be harvested, placed indoors to dry, and when they split, the seeds are shaken out and stored in a dry place indoors. Sow the next spring.

  (2) Sowing: use a shallow pot, wooden box or ground bed, with well-drained coarse-grained soil spread at the bottom, and the surface layer of 2 cm using orchid soil or leaf mold (both need disinfection). After the seeds are evenly scattered, thinly cover with a layer of fine soil. Or spread 0.5-1 cm of chopped sphagnum on top of the orchid soil, sow the seeds directly into the sphagnum without covering. Then water to moisten the pot soil, cover with plastic film or a glass plate, and place in a shady place.

  (3) Management: before emergence, keep the pot soil moist. Generally at 15-20°C, emergence occurs in about 20 days, with a germination rate of 75-85%. After that the cover can be removed, taking care to ventilate and improve the seedlings' resistance. When dry, spray moist with a fine nozzle, and do not wash down the seedlings.

  (4) Seedling separation: deciduous rhododendrons grow relatively fast; when 2-3 true leaves have grown, the first transplanting can be done, with a plant spacing of 2-3 cm. After autumn, when they grow to 2-3 cm tall, dig them up again and transplant into 3-cun small pots, 3 plants per pot. The following year, divide and plant again according to growth; generally after 3-4 years they can bloom. Evergreen rhododendrons are first transplanted after autumn, and transplanted again the next autumn. During the seedling stage, avoid strong light, heavy rain and strong wind; the soil should not be too wet, and watering is still done by spraying.

  Cuttage: this is the most widely used method; its advantages are simple operation, high survival rate, fast growth and stable traits.

  (1) Cuttings: take current-year young shoots that have just lignified, break them off with a heel, trim the frayed end smooth, cut off the lower leaves, leaving 4-5 leaves at the top; if the shoot is too long, the tip can be cut off. If they cannot be inserted immediately after collection, wrap the base with a wet cloth or moss, cover with plastic film, and place in a shady place, where they can be kept for several days.

  (2) Time: in Jiangnan, cuttings are taken before the plum rain season, giving the highest survival rate; West Azalea from late May to early June, Hairy Azalea from early to mid-June, East Azalea and Summer Azalea from mid-to-late June. At this time the cuttings are moderately tender, the weather warm and humid, and the survival rate reaches over 90%.

  (3) Method: for a small number, pot cuttings can be used; for a large number, bed cuttings can be used. The medium can be orchid soil, Huangshan soil, river sand or pumice, perlite, etc., requiring few pathogens, no weeds, and no fertilizer mixed in. Insert the cuttings 1/3 to 1/2 deep, and after inserting, spray with a fine-hole pot and place under a shade shed. The pot bottom needs to be raised one brick; the cutting bed is 20 cm deep, with a 7-8 cm thick drainage layer filled at the bed bottom to facilitate drainage.

  (4) Management: within one month after cutting, the focus is on shading and spraying water, so that the cuttings remain fresh throughout. During heavy rain, avoid rainwater impact; during consecutive overcast and rainy days, pay attention to drainage; spray 1/1000 thiophanate to control black spot disease; in the high-temperature season, increase spraying on the ground and leaf surfaces, and pay attention to ventilation and cooling. Hairy Azalea, East Azalea and Summer Azalea root quickly, about 1 month or so; West Azalea needs 60-70 days. After rooting, the top puts out shoots; if flower buds form, they should be removed. After September, reduce shading so the seedlings gradually become sturdy, and in October a thin fertilizer can be applied. In late October they can be potted. If an electronic leaf automatic misting device is installed on the cutting bed, and the medium is vermiculite or perlite, then no shading is needed. Under full sun, roots form in more than 20 days, the survival rate is over 95%, and they can be transplanted in 2 months.

  Grafting: this is used more when cultivating West Azaleas. Its advantages are: the scion needs only a section of young shoot; the young shoot can be grafted at any time, without restriction; several cultivars can be grafted onto the same plant; it grows faster than cuttings and has a high survival rate. There are many grafting methods; the most commonly used is the young-branch terminal cleft graft, best in May-June, with a survival rate of 90%.

  (1) Rootstock: choose 2-year-old single-trunk Hairy Azalea, requiring the new shoot and the scion to be similar in thickness. Among Hairy Azalea cultivars, 'Yuhudie' and 'Zihudie' are best; generally the original species Rhododendron mucronatum is not used.

  (2) Scion: from the mother West Azalea plant, cut a 3-4 cm long young shoot, remove the lower leaves, leave 3-4 small leaves at the top, and cut the base into a wedge shape, with the cut surface 0.5-1 cm long.

  (3) Method: cut off the current-year new shoot of the Hairy Azalea at 2-3 cm, remove the leaves of that section, make a 1 cm vertical cut, insert the scion, align the cambium, bind with plastic film tape, and put the joint together with the scion into a plastic film bag, tying the bag mouth tightly.

  (4) Management: place under a shade shed, avoiding direct sunlight. Check whether there are water droplets in the bag; if not, open it and spray the scion moist, then tie it tightly again. If the scion does not wilt for 7 days, there is confidence of success; after 2 months remove the bag, and the next spring untie the binding.

  Site: cultivating West Azaleas requires two environments, indoor and outdoor: indoor is for winter cold protection, with the coldest not below -2-3°C. Outdoor is for getting through the hot summer; in the Jiangnan region they are kept outdoors from mid-April to early November, requiring the natural shade of deciduous trees, or artificially set shade sheds, to create a semi-shady and cool growing environment. The ground must have a drainage slope, and the flower pots are placed on battens.

  Pot selection: in production, clay pots with good permeability and low price are all used. Rhododendrons have shallow roots and slow expansion, so cultivation should use small pots as much as possible, to avoid uncontrolled watering that is unfavorable to growth. Regarding plant age and pot mouth size, refer to the following table: 1-2 years old: use 3-cun pots; 3-4 years old: use 4-cun pots; 5-7 years old: use 5-cun pots; 8-10 years old: use 6-cun pots; 11-15 years old: use 7-8 cun pots; 16-20 years old: use 9-cun pots; over 20 years: use 10-cun pots.

  Soil: commonly used is black mountain soil (orchid soil), black in color and light in texture being best. When using, spread it out to sun for several days, pick out debris, sieve out coarse and fine, and fill the pot in layers to ensure smooth drainage. In addition, peat soil, Huangshan soil, leaf mold, pine needle soil, and even mixed soil prepared with coal cinders, sawdust, etc., as long as the pH is between 5.5-7, permeable and draining, and rich in humus, are all acceptable.

  Potting: generally carried out in spring when they leave the house or in autumn when they enter the house; fill the pot bottom with a drainage layer of coarse-grained soil, and after potting place in a bright place for several days to settle, then move to a suitable position. During the seedling stage, repotting is more frequent, once every 2-3 years. After 10 years, they can be repotted once every 3-5 years. Old plants, as long as there are no problems, can go many years without repotting.

  Watering: must be flexibly controlled according to weather conditions, plant size, pot soil dryness and wetness, and growth and development needs. The water quality must not contain alkalinity and must be clean and hygienic. If tap water is used to water flowers, it is best to store it in a vat for 1-2 days, and the water temperature should be close to the pot soil temperature. After November the temperature drops, growth is slow, and water demand is small; when the room is not heated, not watering for 3-5 days is no problem; in late February growth gradually rises, and the water amount should be appropriately increased; from March to June, flowering and shooting, the water demand is large, once a day on sunny days, and if insufficient, supplementary water is needed in the evening; in the plum rain season, with consecutive overcast and rainy days, promptly tilt the pot to pour out water. In the high-temperature season of July-August, water as it dries, and at noon and dusk spray water on the ground and leaf surfaces to cool and increase humidity; in September-October the weather is still hot, and watering cannot be neglected.

  Fertilizing: West Azaleas require thin fertilizer applied frequently; commonly used fertilizers are grass juice water, fishy water and rapeseed cake. Grass juice water is made by composting tender grass and leaves, is the thinnest nitrogen fertilizer, and can be used as water for watering. Fishy water is made from fish offal, heads and tails, and stinking fish and shrimp, etc., adding 10 times water, stored in a vat, sealed and fermented for more than half a year; when using, take the stock solution and add water, applying at 3-5% concentration. This fertilizer is rich in phosphorus, can make leaves glossy and flowers bright, but the next day it should be rinsed once with clean water. Rapeseed cake is a comprehensive fertilizer, also needing to be crushed and composted for several months, then diluted with water for application.

  Shading: West Azaleas must be shaded from May to November, with the shed about 2 m high, and reed curtains with 20-30% light transmittance; the west side should also have curtains hung for shading. The daily shading time can refer to the following table: May 9:00-15:00; June 8:30-16:30; July-August 8:30-17:00, hang curtains at the southeast corner in the morning and the southwest corner in the afternoon; September 8:00-16:00; October 9:00-15:30; November cover curtains appropriately at noon, and after mid-to-late November do not cover; December-April, if the flowering period needs to be delayed, then cover. In this way, West Azaleas can bloom as late as late April and reach full bloom at "May Day."

  Pruning: for seedlings within 2-4 years, in order to accelerate the formation of the framework, flower buds are often removed, or when the new shoot grows to 4-5 cm it is pinched to prompt lateral branches to sprout. Some cultivars have short and numerous new shoots, so pinching is not suitable; instead, branches should be appropriately thinned. Plants 5-10 years old should not bloom too much, and some flower buds should also be removed. After growing into large plants, the main task is to cut off diseased branches, weak branches and branches that disrupt the tree shape, all mainly by thinning cuts.

  Flowering management: when West Azaleas bloom, place them indoors, free from sun and rain, and they can last 1 month. If indoor ventilation is poor, they should not be kept long; after one or two weeks they should be moved. West Azaleas form flower buds in July-August; after autumn, bring them into the house, maintain 20°C, and after half a month they can bloom. Accordingly, they can be made to bloom at New Year's Day and Spring Festival. If kept all along in a low-temperature cold room at 3-4°C, and taken out in mid-September, they will bloom at National Day. After flowering, promptly remove the spent flowers, and add pruning, and carefully maintain them.

  Pest and disease control: the most common pests are red spider mites and lace bugs. Red spider mites are seriously harmful in the high-temperature dry period of June-August, often turning leaves yellow and causing them to fall; they can be killed by spraying 1/1000 dicofol, once a week, 3 times in succession. From May to October there is harm from lace bugs, spreading faster in dry climates; they can be killed by spraying 1/1500 dimethoate or dichlorvos. Brown spot disease is the most common disease, mainly occurring in the plum rain season; brown patches appear on the leaves, infecting in cycles, causing great harm, and it is the main cause of leaf fall. The control method is: spray 1/800 thiophanate or Bordeaux mixture of equal amounts before and after flowering, pay attention to improving light conditions, strengthen ventilation, and burn diseased leaves at any time.

  Artificial pollination and hybridization is a conventional breeding means; cultivars with well-developed pistils and high fruit-set should be selected as the female parent, and pollen should be collected from cultivars with special ornamental value in flower color and flower type. Pollen can be refrigerated in an ice bottle for long-distance transport. Pollination is best chosen when the stigma secretes mucus; to increase the success rate, pollination should be repeated 2-3 times. Because self-pollination fruit-set is very low, emasculation beforehand is unnecessary, and in cold climates with no insect interference, bagging is also unnecessary.

  After the seeds are sown, deciduous rhododendrons bloom after 3 years; selection must be carried out, and after another 2-3 years of cultivation, when traits are stable, selection is carried out again; those that meet the ideal are only a few percent. Hybridization, selection and cultivation are long-term work. Domestically, in terms of horticultural cultivars, the new varieties obtained by hybridization already number in the hundreds, with very rich flower colors and flower types. But the growth and development process of evergreen rhododendrons is even longer, and hybridization and breeding work has just begun. Horticultural cultivars themselves are complexes of multiple genes, and various variations often appear in flower color and flower type; new cultivars can also be obtained by using the bud sport phenomenon of branches. Among West Azaleas, 'Qingnv', 'Xinhong', 'Fengbei', 'Qiushuibo', etc. were all obtained by bud sport selection. The rhododendron is an excellent bonsai material. It has the advantages of slender branches and leaves, evergreen in all four seasons, tolerance to pruning, strong sprouting ability, unusual roots and branches, few pests and diseases, abundant and colorful flowers, and long life. If techniques such as bending branches, braiding and tying, trimming and raising roots are used, and artistic forms such as straight trunk, curved trunk, double trunk, multiple trunk, forest, connected-root, cliff-hanging, raised-root and rock-attached are carried out, it can be made into a stump bonsai beautiful in form, branches and leaves, and flowers alike.

  Besides being grown in pots for ornamental display, Rhododendron mucronatum, Rhododendron obtusum (East Asian azalea), and Rhododendron indicum (summer azalea) can all be used to decorate courtyards. Whether a single plant or a few plants are used to accent a small patio or a corner by a wall, or they are planted in clumps and drifts across hillsides winding through woods, along streams and roadsides, or beside rocks on lawns, they can all form beautiful landscapes. Rhododendrons can also be used to create flower-tube green screens and ground-cover plants. In late spring they are ablaze with profuse blooms, in summer they are dense and verdant, and in autumn and winter they still have colorful foliage, so they can be enjoyed in all four seasons.

  In addition, rhododendrons also have edible and medicinal value. The flowers of Rhododendron simsii (mountain azalea) taste sour and are non-toxic, and can be eaten raw; the flowers of Rhododendron decorum and Rhododendron crassipes are still a fine vegetable for the people of central Yunnan; the branches, leaves, and flowers of Rhododendron molle (yellow azalea) can be soaked and composted to make insecticidal pesticide; Rhododendron dauricum and others can be used to make medicine. The bark and leaves of some species are rich in tannins and can be used to extract tannin extract; the wood and root burls of rhododendrons are fine-grained and tough, and can be made into bowls, chopsticks, basins, alms bowls, tobacco pipes, root carvings, and other daily-use crafts and art pieces.