How to Grow Camellias? Camellia Growing Methods and Precautions

Camellia is also called camellia, and is one of China's ten traditional famous flowers. Its leaves are emerald green and glossy, evergreen all year round, with large and brightly colored flowers, rich flower forms, and a long flowering period. It is an excellent flower for garden landscaping and indoor decoration. So, what are the growing methods for camellias? What special points need attention during the growing process? Let us learn about them together.

I. Growing Methods for Camellias

1. Soil Selection

Camellias generally prefer a high-temperature and humid environment and are not very picky about soil quality, but it is best to use fertile, moist, well-drained acidic soil (pH 5-6.5), and soil that is not dry in summer and is close to neutral.

2. Fertilizer and Water Management for Growing Camellias

Camellias like fertile, loose, slightly acidic loam or humus soil, and can grow within a pH range of 4.5—6.5. They require good drainage and no waterlogging, so as to avoid root rot. However, they require high air humidity and are averse to dryness. In areas with annual rainfall above 1200mm, as long as water is drained promptly after heavy rain, they can all grow well. Therefore, during seedling raising and cultivation of camellias, they should be watered frequently to keep the soil and air moist. Fertilizer should be applied many times at low concentration, and one-time fertilization at high concentration and large dosage must be avoided.

In summer, do not let them become especially dry, and water them every day. To keep the flower pot from drying out, irrigation-style watering is better. In pot cultivation, if camellias form buds but do not bloom or even drop their buds, this is caused by insufficient water. Therefore, when buds are forming, mist frequently to increase humidity and prevent flower drop.

In winter, mix organic fertilizer and chemical fertilizer and apply as a base fertilizer. When flower bud differentiation occurs, apply fertilizer of the same composition again.

3. Pot Cultivation and Care for Growing Camellias

For potted camellias, clay flower pots are suitable, especially for young camellia plants. The potting soil can be prepared by mixing 6 parts leaf mold, 1 part cake fertilizer residue, and 3 parts sandy loam, or by mixing 3 parts leaf mold, 4 parts sandy loam, and 3 parts compost. Potting is best done in early spring from March to April or from late September to early October. When planting, place broken tiles at the bottom of the pot to facilitate drainage. Do not apply base fertilizer, so as to avoid burning the new roots.

When potting, plant the small soil-ball cutting seedling in the pot. After planting, water thoroughly until water seeps from the bottom of the pot, and place in a ventilated shady spot. Pay attention to humidity; if necessary, cover with a plastic bag, but the temperature inside the bag must not exceed 25°C, otherwise it will be difficult to survive. After 8-10 days, place in a ventilated semi-shady spot. During the growth period, watering should be based on seasonal changes, with the principle of keeping the potting soil moist. Both excessive dryness and excessive moisture are unfavorable to plant growth.

During the growth and sprouting period, the amount of watering should be gradually increased. After the new shoots stop growing (around late May), watering should be appropriately controlled to promote flower bud differentiation. During the plum rain season, prevent water accumulation in the pot from causing root rot. In summer high temperatures, water once each in the early morning and evening, and at the same time spray around the plant to increase air humidity. Residents in high-rise buildings can place it in the living room or corridor to spend the summer, and move it to the balcony before 9 a.m. or after 5 p.m.

In winter, the plant enters dormancy, so the frequency of watering should be reduced; topdressing should mainly be decomposed dilute liquid fertilizer, avoiding concentrated fertilizer and raw fertilizer. In early spring, apply liquid fertilizer mainly based on nitrogen fertilizer once every 10 days. Apply 1-2 times continuously to promote branch growth and leaf development. From May to August, apply fertilizer combining nitrogen and phosphorus with phosphorus as the main component once a month to promote flower bud differentiation. During the hottest days, attention should be paid to appropriately controlling fertilizer. From September to October, apply fertilizer mainly based on phosphorus and potassium to promote further growth of flower buds.

4. Propagation Methods for Growing Camellias

(1) Camellia Grafting Propagation

Using the large rootstock water-insertion grafting method for propagation gives a high survival rate, and the size of the rootstock is not limited. After grafting, growth is fast and the tree form is established early. One rootstock can be grafted with multiple branches and buds, and on a larger rootstock, multiple varieties can also be grafted at the same time, giving good ornamental value. The grafting period is long, and it can be carried out during the growth period except during the flowering period.

① Rootstock selection: choose vigorous-growing white-flowered or red-flowered camellia oil tea without pests and diseases, with the grafting site thicker than 1cm.

② Scion selection: choose plump and robust buds and shoots, about 10-15cm long, retaining 1-3 leaves at the upper part. If grafting in large quantities, the selected scions can be promptly placed in a basin or bucket, sprayed with water, and then covered with a wet towel to maintain the moisture of the scions. The scions must be moderately mature; both too old and too tender are difficult to survive.

③ Grafting: first choose a smooth surface at an appropriate part of the rootstock, and use a grafting knife to cut a 3-5cm long cut surface in the phloem. Then cut once between the relatively straight phloem and xylem 3-5cm above the base of the scion, with a length slightly shorter than that of the rootstock, trying not to damage the xylem. Then align the cambium layers of the two, bind with plastic film, cover the upper part of the scion with a plastic bag, and cover the base with a glass bottle, plastic bottle, etc. filled with clean water, with the scion immersed in water about 2-3cm. Within 30 days after grafting, keep the base of the scion submerged in water to prevent water loss and leaf shedding, and keep the water clean. Generally, flowers can be produced in the second year after grafting.

④ Waterproofing the graft union: because the surface of the scion is relatively rough, it easily absorbs water and moistens the graft union, affecting healing. The moisture-proofing method is to apply a ring of vegetable oil, wax, or paint 0.5cm wide between the lower part of the graft union and the water bottle.

⑤ Post-grafting management: one month after grafting, if the grafted bud is plump and the leaves are green, it indicates that the graft has survived. After 45-60 days, the plastic bag can be removed, and after another week, the water bottle can be removed. At the same time, the "tail" below the graft union and the rootstock above the graft union can be cut off, and the binding can be appropriately loosened. After 3 months, the binding can be completely removed, but not too early, otherwise survival will be affected.

(2) Camellia Cutting Propagation

Suitable for garden varieties that root easily.

① Selection of cuttings: to adapt to the local environment, cut current-year branches from camellia plants that have grown locally for many years. The longer they have grown locally, the more stable their adaptability to the local environment, and the easier the camellia seedlings bred from them are to cultivate.

Because camellias are affected by the northern environment, their physiological performance has already changed, and to a large extent their inherent growth habits have changed, so they have basically adapted to the local soil, water, climate, and so on. Cuttings should be cut from the top 4-5 nodes of the shoot tip, about 8cm long. As they are cut, remove the lower leaves, keep 2 upper leaves each cut in half, and then insert them into the pot for rooting.

② Cutting time: mid-to-late June is the suitable period for cuttings. At this time, most current-year branches have become woody or semi-woody, are rich in nutrients, and the cut surface has active meristematic capacity, strong regenerative ability, fast callus formation, fast rooting, and easy survival.

③ Cutting medium: choose an earthen pot with a large bottom hole for cuttings, and before filling with soil, first cover the bottom hole with double-layer gauze. Use pure leaf mold as the cutting soil, as it has good air permeability and is slightly acidic, suitable for camellia rooting and growth. Before cuttings, scald the potting soil thoroughly and evenly with boiling water for disinfection.

④ Cutting method: before inserting, first make holes with a small bamboo stick to avoid rubbing and damaging the cortex of the cuttings. The spacing should be such that the leaves do not shade each other. After inserting, immediately spray thoroughly and evenly with cold boiled water, until water drains from the bottom hole of the pot.

II. Precautions for Growing Camellias

1. Be careful not to expose camellias to scorching sunlight

Camellias prefer a semi-shady and semi-sunny environment and like warmth and humidity. The most suitable temperature for camellia growth is 15-25°C, so it is suitable to plant them in a place with semi-shade or diffused light in summer, full light on the south side in winter, and a windbreak on the north side. During summer high temperatures, spray water mist on the branches and leaves and around them to lower the temperature and prevent dryness. From June to September, shading treatment should be carried out.

2. Be careful not to arbitrarily change the orientation of camellias

Camellias have relatively poor adaptability. During the period from April to September when they sprout and grow buds, the orientation of camellias should not be arbitrarily changed, so as to avoid the leaves originally facing the shady side suddenly contacting strong light and falling off.

3. Be careful not to use alkaline soil to grow camellias

Camellia roots are fragile, so loose, well-drained, slightly acidic soil should be used. Neither clayey nor alkaline soil is suitable, and calcareous soil must not be used at all. Moreover, the potting soil is best replaced once every two to three years. When changing pots, note that base fertilizer should be placed at the bottom of the pot; a small amount of hair, bone meal, chicken feathers, poultry manure, and other substances containing calcium superphosphate can be used. It is better to carry out repotting between the two solar terms "Rain Water" and "Beginning of Summer."

4. Be careful not to overwater camellias or apply overly concentrated fertilizer

Camellias have fleshy roots, and overwatering easily causes root rot, so water must be applied in appropriate amounts. During drought and high temperatures, water the leaf surface twice a day. Camellias like fertilizer. Apart from the flowering period, fertilizer can usually be applied lightly and frequently, but overly concentrated fertilizer must be avoided, otherwise it easily damages the roots and causes the plant to be burned to death. Fertilizer should be mainly phosphorus and potassium fertilizer, with nitrogen fertilizer secondary. It is best to mix three parts decomposed cake fertilizer, chicken manure, or human manure with seven parts water. Apply once about every twenty days in summer and autumn to promote vigorous growth and robust plants.

III. Pest and Disease Control for Growing Camellias

1. Camellia Yellow Leaf Mottle

Symptoms: Camellia yellow leaf mottle disease may be a whole-plant disease caused by virus infection. In the early stage of the disease, unclear mottled symptoms of uneven color appear on the leaves, which are faded green or grayish white, and later gradually become dark yellow mottling or colored spots, with the colors of the spots being bright. The mottling is rather irregular in shape and varies in size, and the edges of the diseased spots are extremely obvious. The petals of camellias sometimes also show mottling or marbled markings. The leaves of affected plants become thinner, chlorophyll decreases, and growth vigor weakens.

Control methods: ① Avoid using branches from diseased plants for cuttings, and do not use diseased plants as rootstock or collect scions from them. ② If diseased plants are found, immediately pull them out and destroy them. ③ Ordinarily, agents for controlling viral diseases such as Virus Ling and Virus Qing can be used for prevention and control.

2. Camellia Algal Leaf Spot

Symptoms: Camellia algal leaf spot can occur on both the leaves and young stems of camellia. The pathogen can infect both the front and back of leaves, but mostly the front. In the initial stage, affected leaves show needlehead-sized small round spots from grayish white to yellow-brown, sometimes slightly cross-shaped, and later gradually expand radially outward, forming round, slightly raised felt-like spots. The edges of the diseased spots are irregular, grayish green or dark brown, with fibrous fine lines on the surface, 2-15 mm in diameter. In the later stage, the color becomes darker and the surface is relatively smooth. On affected young branches, red-brown hairy small stalks appear in the diseased parts, and the spots are long oval. In severe infections, the branches dry up and die.

Control methods: ① Strengthen cultivation management, fertilize reasonably, prune in time, remove diseased branches and leaves, avoid excessive shading, maintain ventilation and light transmission, and improve plant resistance. ② During the growing season, spray 0.5%-0.7% half-strength Bordeaux mixture, or first spray 2% potassium chloride on the leaves and then spray 0.25% copper preparation, for better control effect.

3. Camellia Gray Leaf Spot

Symptoms: Camellia gray leaf spot mainly harms leaves, but also infects new shoots. In the early stage of the disease, light green or dark brown needlehead-sized small spots appear on the underside of leaves, gradually expanding into round, semicircular, or irregular diseased spots, brown to black, with the center turning grayish white in the later stage and the edges reddish brown and slightly raised. The diseased part and the surrounding healthy tissue have clear boundaries. Sometimes several diseased spots connect with each other and occupy most of the leaf, producing dense black small spots on them. When moist, black viscous matter overflows from the black granular spots, namely the pathogen's conidial stroma. In severe cases, the diseased leaf tissue ruptures, breaks apart, and even falls off to form holes. Infected new shoots show brown water-soaked long streaks, generally 3-4 mm long, sometimes reaching 10-30 mm. The diseased spots are constricted and sunken, with discontinuous longitudinal cracks. Finally, the diseased shoot often falls off from the base.

Control methods: ① Potted flowers should not be placed too densely, to avoid increased friction and causing wounds. During the peak disease period, avoid spraying water from the top of the plant when watering; instead pour it in from the edge of the pot to reduce leaf surface humidity. ② In autumn and winter, remove diseased residues such as dead branches and fallen leaves. During the growing season, promptly remove diseased branches and leaves and burn them in a centralized manner. ③ Spray 150-fold high-fat film solution or 50% amobam 1,000-fold solution, 3-4 times continuously.