What are the key points to note when planting camellias?

1. Soil

Everyone knows that camellias generally are suited to growing in slightly acidic soil, with a pH value between 5.5 and 6.5. Alkaline soil, heavily clayey soil, or waterlogged ground is not suitable for planting camellias. Camellias planted in soil that is too acidic or too alkaline will grow and develop poorly. Southern red-yellow soil, northern black chernozem soil, and humus soil from hillsides (mountain soil) are usually slightly acidic. But try not to use river mud, because river water is now fairly seriously polluted. Interested friends can go to a chemical store to buy pH test paper to test it, or if your camellia leaves gradually lose their green color and turn yellow, it means your camellia's soil has become alkaline. You can dilute ferrous sulfate according to the instructions on the package and water it on, and stop using it once the green color returns.

2. Sunlight

Without light, not only can photosynthesis not occur and life activities not be carried out, it is also impossible to produce large, brightly colored, gorgeous flowers. Camellia leaves have phototropism; they need sunlight but cannot tolerate strong light, so they need plenty of diffused light. They most dread long-term exposure to the blazing sun, which burns the leaves. In summer, when the temperature is above 35 degrees (some suggest above 30 degrees), shade screens should be set up.

Tips

*I like to use a shade net (a light-transmitting bamboo mat also works). This both prevents the blazing sun and lets in about 25% direct sunlight. But do not forget to spray water on the leaves and around the camellia to lower the temperature (described below).

*Shade nets are sold at flower markets, the black kind with small holes in it.

3. Temperature

Camellias are generally in their vigorous growth period at temperatures of 15-25°C, when they need plenty of water and nutrients. Above 35°C growth slows down. Camellias are relatively cold-resistant; generally -7°C is not a big problem. I only bring them indoors when it is -5°C with freezing, but they cannot be brought directly into a room with a higher temperature (discussed later). Generally, field-planted camellias are more cold-resistant, but I have no experience with field-planted camellias so I dare not say too much. I only know that field-planted camellias are relatively easier to grow than potted ones, and generally can overwinter safely. And camellias that have gone through an entire winter often produce larger and more brilliantly colored flowers than camellias kept in a greenhouse. This is vernalization (discussed later).

4. Watering

Water directly affects the process of camellia growth and development; it is the lifeline of the camellia. Because water is a raw material for photosynthesis and the main component of cell protoplasm, and through water transpiration it can also regulate the camellia's body temperature. With too much water, camellias will show leggy growth, inhibited flower bud differentiation, and may even suffer root rot or drowning death; with too little water, camellias will show wilting and be unable to carry out normal life activities. Because camellias have abundant flowers and leaves or are cultivated in pots, the water absorbed by the root system often cannot meet the need to replenish the water lost through evaporation from the aboveground parts; in order to maintain the water balance within the camellia, frequent watering is needed. Potted camellias especially need particular attention; in winter the potting soil should be dry. This is because in winter the camellia's growth enters a resting stage, and its physiological water requirement decreases; moreover, being too wet in winter easily causes the potting soil to freeze and damages the root system. In summer the potting soil should be moist. This is because summer is precisely the high-temperature and dry season, and also the period of vigorous camellia growth, requiring large amounts of water. As for watering time, in spring and autumn it is best in the morning and afternoon; in summer the midday temperature is too high, so it is best in the early morning and evening; and in winter, it is best at noon when the temperature is higher. In high-temperature and dry weather, watering 2-3 times a day is needed to ensure the camellia's normal growth and development.

5. Fertilizing

Camellias need sufficient fertilizer to have sturdy branches and trunks and abundant flowers and leaves, and to have a certain ornamental value. However, if a compound fertilizer is used whose nitrogen, phosphorus, and potassium contents are 26%, 20%, and 20% respectively, then it is especially suitable for flower growth and development. Nitrogen fertilizer can promote camellia growth and form plants with abundant branches and leaves; phosphorus fertilizer can promote bright camellia flower color and root development, etc.; potassium fertilizer can promote healthy camellia growth and root system development, which is beneficial for overwintering. In fertilizing, attention should also be paid to the different growth stages of the camellia, applying timely, appropriate amounts and appropriate methods, combined with nitrogen, phosphorus, potassium fertilizers and various trace element fertilizers, to achieve good results. Organic fertilizer must be fully decomposed before application, and generally the principle is small amounts applied frequently. In March, before the spring shoots sprout, more nitrogen fertilizer should be applied; in June, during the flower bud formation period, more phosphorus fertilizer should be applied; in September, during the bud formation and flowering period, and thereafter, more phosphorus and potassium fertilizers should be applied. The fertilizing interval should not be less than 10-15 days.

Camellia planting methods | Camellia planting techniques | Camellia growing methods

Camellia originated in China. In the early 7th century AD, Japan introduced camellias from China, and by the early 15th century it was introducing Chinese camellia varieties in large quantities. In 1739, the United Kingdom first introduced Chinese camellias, and afterward camellias spread to European and American countries. To date, countries such as the United States, the United Kingdom, Japan, Australia, and Italy have developed rapidly in camellia breeding, cultivation, and production, and have entered the stage of industrialized production, with interspecific hybrids, intraspecific hybrids, and new varieties continuously coming onto the market.

China has a long history of cultivating camellias. Camellia cultivation has existed since the Southern Dynasties. In the Tang Dynasty, camellias were cultivated as precious ornamental plants. By the Song Dynasty, camellia cultivation was already very popular. In the Southern Song Dynasty, camellias from Wenzhou were introduced to Hangzhou and developed rapidly. In the Ming Dynasty, "Flower History" described and classified camellia varieties. By the Qing Dynasty, camellia cultivation was even more flourishing, and camellia varieties continuously emerged. Since 1949, China's camellia cultivation level has improved to a certain extent, and variety selection and breeding have further developed. At present, China has more than 300 camellia varieties. Batch production has begun in Zhejiang, Fujian, Jiangsu, and other places. At present, it has become the main potted ornamental flower and plant in the flower market in winter.

[Morphological characteristics and varieties]

Camellia is an evergreen broad-leaved shrub. Leaves are alternate, leathery, elliptical, with serrated edges, dark green. Flowers are borne singly or 2-3 together at the tips of branches or in leaf axils. Flowers are single, semi-double, or double. Common varieties include single-petaled types such as 'Chenxi', with crinkled-edged, pure white flowers; 'Saijinguang', with white flowers marked with peach-red lines and sprinkled with fine dots; 'Dahua Jinxin', with large red flowers, flower diameter 6-7 cm; semi-double types include 'Sai Luoyang', with red flowers with white blotches; 'Da Songzi', with dark red flowers; 'Zui Yangfei', with pink flowers; 'Xingtao Mudan', with peach-red flowers. Double types include 'Bai Baozhu', with pure white flowers; 'Hong Furong', with oleander-red flowers; 'Hua Furong', with white flowers with red lines; 'Hua Baozhu', with pink flowers with irregular red stripes; 'Wuhe Pengqiu', with large red flowers; 'Hua Foding', with large red flowers with a small amount of white blotches; 'Hong Shiba Xueshi', with red flowers; 'Chidan', with large red flowers; 'Hua Heling', with pale red flowers with white spots. Foreign-bred varieties include Adolphe Audusson, with large, dark red, double flowers. Alba Plena, with large, white, double flowers. Berenica Boddy, with pale pink, semi-double flowers and strong cold resistance. Debutante, with large, peony-form, pale pink flowers. Donckelarii, with red flowers with white marbled stripes, semi-double. Elegans, with large, anemone-form flowers, rose-red with white spots. Finlandia, with pale pink, semi-double flowers. Glen 40, with large, dark red, double flowers. Herme, with pink flowers with irregular white edges and deep pink stripes, semi-double. Kumasaka, with rose-form, rose-red flowers. Magnoliaeflora, with pale red, semi-double flowers. Mathotiana, with large, rose-form, dark red, double flowers. Purity, with white, rose-form, double flowers. Among hybrid camellias there are Donation, with large, pink, semi-double flowers; Fragrant Pint, with small, peony-form, deep pink flowers that are very fragrant.

[Biological characteristics]

Camellia originated in China. It likes warm, humid, and semi-shaded environments. It fears high temperatures and avoids the blazing sun.

The suitable growth temperature for camellias is 18-25°C, 13-18°C from March to September, and 10-13°C from September to the following March. When the temperature is above 12°C, sprouting begins; above 30°C, growth stops; the initial flowering temperature is 2°C, and the suitable temperature for flowers to open is 10-20°C. Cold-resistant camellia varieties can tolerate -10°C for a short time; ordinary varieties tolerate -3 to -4°C. When the summer temperature exceeds 35°C, leaf scorching will occur.

Camellias are suited to an environment with sufficient water and humid air, and avoid dryness. In the high-temperature and dry summer and autumn, watering or spraying should be done promptly; the relative air humidity is best at 70%-80%. During the plum rain season, pay attention to drainage to avoid waterlogging and root rot.

Camellia is a semi-shade plant, suitable for growing under diffused light, and fears direct sunlight and blazing exposure; seedlings need shading. But long-term excessive shade is unfavorable to camellia growth, resulting in thin leaves and few flowers, affecting ornamental value. Mature plants need more light to favor flower bud formation and flowering.

For open-field cultivation, choose deep, loose soil with good drainage; a pH of 5-6 is most suitable; alkaline soil is not suitable for camellia growth. For potting soil, use fertile, loose, slightly acidic loam or leaf mold.

[Growing methods]

Commonly used methods are cuttings, grafting, layering, sowing, and tissue culture.

Cutting propagation: mid-June and around the end of August are most suitable. Choose as cuttings current-year semi-ripened branches from the outer part of the crown that are full in tissue, with intact leaves and plump leaf buds, 8-10 cm long, leaving 2 leaves at the tip. When cutting, keep a little old branch at the base if possible; after insertion it easily forms callus tissue and roots quickly. Cut the cuttings in the early morning and insert them as soon as they are cut, inserting about 3 cm into the substrate; when inserting, the leaves should overlap each other, and after insertion press firmly with fingers. Shallow insertion is better, as this allows air flow and fast healing and rooting. The cutting bed needs shading, daily misting of the leaf surface to keep it moist, and the temperature maintained at 20-25°C; about 3 weeks after insertion healing begins, and rooting occurs after 6 weeks. When the roots are 3-4 cm long, transplant into pots. When cutting, dip the base of the cuttings in a 0.4%-0.5% indolebutyric acid solution for 2-5 seconds, which has a clear effect of promoting rooting.

Grafting propagation: often used for varieties that are difficult to root from cuttings or for which propagation material is scarce. Grafting in May-June, when the new shoots have become semi-lignified, gives the highest survival rate, and after successful grafting, buds sprout and shoots grow quickly. The rootstock is mainly Camellia oleifera; seeds are collected in October, stored in sand in winter, sown in early April of the following year, and when the seedlings grow to 4-5 cm they can be used for grafting. Using the tender shoot cleft grafting method, use a blade to cut off the embryo bud portion of the bud rootstock, make a vertical cut upward along the pith at the center of the cross-section of the hypocotyl, then take one node of camellia scion and also cut the base below the node into a regular wedge shape, immediately insert the prepared scion into the bottom of the rootstock cleft, align the cambium on both sides, bind with cotton thread, and cover with a clean plastic bag. Remove the bag after about 40 days; sprouting and shoot growth occur only after about 60 days.

Layering propagation: in the plum rain season, choose vigorous 1-year-old branches, 20 cm from the tip, perform ring-barking 1 cm wide, wrap with leaf mold and then cover with plastic film; rooting occurs after about 60 days, and when cut off they can be directly potted, with a high survival rate.

Seed propagation: suitable for single or semi-double varieties. Seeds mature in mid-October and can then be sown. Shallow sowing is better; use vermiculite as the substrate, cover 6 mm, room temperature 21°C, light for 10 hours each night, which can promote seed germination; germination begins 15 days after sowing, within 30 days the seedlings reach 8 cm in height, and when the seedlings have 2-3 leaves they are transplanted.

Tissue culture propagation: the explant is often a seedling; after routine disinfection it is cut into 1 cm lengths and inoculated on MS medium supplemented with kinetin 1 mg/L, 6-benzylaminopurine 1 mg/L, and indoleacetic acid 0.1 mg/L; after 4 weeks of culture only callus tissue forms, without shoot formation. After transfer to new medium, a single 4 cm shoot begins to form, then it is soaked in indolebutyric acid 0.5 mg/L solution for 20 minutes, then transferred to 1/2 MS medium, and roots grow after 4 weeks. After growing for 8 weeks on the rooting medium, the seedlings are transplanted into pots containing perlite and peat.

[Cultivation management]

Potted camellias commonly use 15-20 cm pots. Camellia root systems are fragile, so when transplanting, be careful not to damage the roots. For potted camellias, repot each year after flowering in spring or in September-October, prune off leggy or dead branches, and replace with fertile leaf mold. Camellias like moisture, but the soil should not be too wet, especially in pots; too-wet potting soil easily causes root rot. Conversely, if irrigation is insufficient and the soil is too dry, the leaves curl, which also affects flower bud development.

After spring repotting, camellias do not need immediate fertilizing. After summer begins, during the vigorous stem and leaf growth period, fertilize once every half month or use "Huiyou" 21-7-7 acid fertilizer. From bud appearance in September to the flowering period, apply 1-2 additional phosphorus-potassium fertilizer applications. In late summer and early autumn, camellias begin to form flower buds; each branch tip should keep 1-2 flower buds, not too many, so as to avoid consuming nutrients and affecting the opening of the main flower bud. When removing buds, pay attention to the position of leaf buds to maintain a beautiful plant shape. At the same time, remove dried and useless buds by hand as you go.

[Pest and disease control]

When camellias are cultivated indoors or in greenhouses, if ventilation is poor, they are easily harmed by red spider mites and scale insects; these can be controlled by spraying with 40% omethoate emulsifiable concentrate at 1000 times dilution or by washing them clean. In the plum rain season, when air humidity is high, anthracnose often occurs; it can be controlled by spraying with equal-part Bordeaux mixture or 25% carbendazim wettable powder at 1000 times dilution.

[Post-production handling]

Camellias have a graceful crown, bright green leaves, large and brightly colored flowers, and a long flowering period, blooming right around New Year's Day and the Spring Festival. Potted plants placed in guest rooms, studies, and balconies present an elegant and luxurious atmosphere. Planted in courtyards, accompanied by flower walls and rocks in front of pavilions, the scenery is natural and pleasant. During storage and transport, prevent high temperatures and dry air, otherwise buds and flowers easily drop, affecting quality.

Notes on planting and propagating camellias

Understand the camellia's attributes: a shade plant, liking a semi-shaded and semi-cool growing environment, preferring acidic soil, not tolerant of salinity and alkalinity, with a well-developed root system and fleshy young roots. Camellias require fertile, loose soil with good air permeability.

Camellias like slightly acidic mountain red (yellow) loam with relatively high humus content and good aeration, with a pH value between 5 and 6.5; alkaline soil or heavily clayey soil cannot be used as the potting substrate for camellias.

Soil preparation: mountain soil (matured red loam used for growing crops) 50%, sawdust or edible mushroom residue 40%, cake fertilizer powder or livestock manure and phosphate fertilizer powder 10%; mix the three well, add an appropriate amount of water, bag, and mature; more than 20 days in summer and autumn, more than 30 days in spring and winter. This kind of soil is not only loose and air-permeable but also retains fertilizer and water, suitable for camellia growth and development.

Camellias need suitable light but also fear high temperatures and direct blazing sunlight. In spring and late autumn, move the camellia to a balcony or ground area with more light to receive all-day sunlight, promoting plant growth and development, promoting flower bud differentiation, and making flower buds robust. When summer arrives with the strongest sunlight, move the pot to a shaded, sunny-avoiding, well-ventilated environment for care; it can also be moved to a north balcony or to the lower inner part of a south balcony for cultivation. A 75% shade net can also be used, covering the plant from 9 a.m. to 5 p.m. to avoid direct blazing sunlight causing leaf damage or withering of small plants; if conditions permit, move the camellia under a sun shed to safely pass the summer.

Temperature is an important condition for camellia physiological activity. Camellias like warmth, and the most suitable temperature for growth is 18°C to 25°C, with relative humidity 60% to 65%. From flower bud formation to flowering, camellias take 180 to 240 days.

Camellias have many leaves and a large leaf area, and transpire quickly. Camellias like a relatively humid climate and also like moist soil. Therefore, potted camellias should be given sufficient water; during the spring and autumn growing seasons, water once a day; in summer, especially during the "dog days," water once each morning and evening; if the ground is dry, also water or spray the ground around the flower pot and the surrounding area once or twice to maintain a certain air humidity, and the plant will grow luxuriantly. At the same time, note that because of frequent watering, and because most households use tap water, over time the soil in the pot will become alkalized. For this reason, when watering, add 0.5% to 1% ferrous sulfate water once a month, or use 5% to 8% edible vinegar solution to spray the leaves. Camellias like moist soil but also fear water accumulating in the pot; on rainy days, if water accumulates in the pot, it must be drained promptly to avoid the root system being soaked in water, suffocating, and rotting.

Camellias are fertilizer-loving flowers; because the tree is vigorous, has many leaves, and a long flowering period, they also need a lot of fertilizer. In fertilizing, apply sufficient liquid fertilizer, and combine with repotting to apply sufficient slow-release fertilizer; according to pot size, apply 3 grams to 80 grams of decomposed cake fertilizer powder or dried chicken and duck manure per pot, placed at the bottom of the pot and mixed evenly with the bottom soil.

According to the plant's growth stage, apply additional organic fertilizer. Except during the coldest and hottest times in winter and summer, apply decomposed cake fertilizer water once or twice a month. The fertilizing method: scrape away about 2 fen of soil at the pot edge, pour the liquid fertilizer into the trench and immediately cover with soil to avoid odors. You can also apply decomposed cake fertilizer powder at the pot edge and mix it evenly with the potting soil, letting the flowers slowly absorb it. Urban flower lovers can buy special flower fertilizer at flower markets, which is both hygienic and safe. To make camellias grow better, during the vigorous growth period of camellias, carry out foliar fertilization once or twice a month, spraying the leaves with 0.2% to 0.3% monopotassium phosphate and 1% to 2% plant growth hormone.

Fertilizing principles: mild rather than heavy, dilute rather than concentrated, less rather than more; must adhere to the method of light fertilizer applied frequently, and especially do not apply raw fertilizer.

Camellias like to grow in an environment with moderately flowing air, and most love a gentle breeze; they like the moisture brought by the southeast wind, but fear the northwest wind and strong winds, which make water evaporate too quickly, causing the camellia's supply and demand to become unbalanced, and the branches and leaves are easily damaged, causing bud and flower drop. In winter, camellias should be kept in a wind-sheltered, sunny environment with a certain temperature and humidity. In spring and autumn, move the pot to the balcony so it gets ventilation and light and is swayed by the breeze; this not only makes the plant grow well but also favors flower bud differentiation and flower bud growth and development, and can also reduce the occurrence of pests and diseases. Many years of practice have shown that moderate ventilation and suitable light can play a role in preventing pests and diseases.

1. Cuttings. In the rainy season of May-June, choose a young mother tree and cut a 1-year-old tender branch from the tip, about 10 cm long; remove the lower leaves, flatten the cut below the node with a blade, keep one terminal bud and one lateral bud at the tip and 2-3 leaves, and insert into a medium of river sand or gravel, with insertion depth 1/3-2/3. After insertion, cover with a straw curtain for shade, strengthen misting of the leaf surface, and maintain air humidity in the cutting bed to promote rooting. To improve the survival rate of cuttings, soak the cuttings in 50-100 ppm ABT rooting powder solution for 8-12 hours.

2. Grafting. Choose vigorous seedlings or camellia varieties that root easily from cuttings as the rootstock, cut off at 4-5 cm from the ground diameter, split through the pith about 1.5 cm deep, use 1-2-year-old branches as scions, keep 1-2 leaves on the upper part of the scion, cut the lower part into a wedge shape, insert into the cleft of the rootstock, make sure the cambium of both sides fits closely, and then bind tightly with plastic tape.

Management after grafting. After grafting, cover the scion with a plastic bag and tie it below with a string, but not too tightly, so that water droplets form inside the bag and continuously drip onto the rootstock. Then add a paper bag on the outside of the plastic bag to shade direct sunlight.

3. Bud cuttings. Take each bud node as a section, keep one leaf, about 1.5 cm long, cut obliquely at the lower part, then insert into the medium, with the depth just covering the branch. This method can make full use of branches and is suitable for large-scale propagation needs.

Potting soil selection: choose slightly acidic, loose, fertile mixed soil as the potting soil. The ratio of the mixed soil is 6 parts garden soil, 3 parts pine leaf humus soil, and 1-2 parts sandy soil.

Pot selection: clay pots are better for cultivation. The ratio of pot size to seedling is: for a camellia with seedling height 40-50 cm and crown width 20-25 cm, the pot mouth diameter is about 20 cm. Other sizes follow the same pattern. For commercial seedlings, purple clay pots are better and can improve the ornamental effect.

Pot seedling selection: choose plants that are vigorous, with a main trunk, single-stemmed without branches, a graceful crown, tender green leaves, and no pests or diseases.

Watering management: for newly planted seedlings, water thoroughly the first time, then water frequently within 2 months to keep the potting soil moist. Afterward, water as with other potted flowers and plants. The frequency depends on the climate, following the principle of keeping the soil moist. Water more in spring to meet the needs of sprouting and shoot growth; in summer it is best in the morning and evening; in the rainy season prevent water accumulation; in autumn drought, water promptly; in winter, to prevent freezing, water at noon.

Shading and cold protection: camellias should be given sufficient sunlight in spring and the rainy season, and shaded and cooled in summer and autumn; when the winter temperature drops to zero degrees, they need to be moved indoors for cold protection.

Flowering control: mainly through variety selection, temperature control, and hormone treatment to achieve the purpose of earlier or delayed flowering. For example, to delay flowering, choose late-flowering varieties and subject them to low-temperature control (a cold storage above 2-3 degrees, storing plants that have been wrapped for cold protection), which can delay flowering by one month.