How to grow camellias? A detailed guide to camellia cultivation methods

Camellias are beautiful in form, with rich and glossy leaves and lovely, brilliantly colorful flowers. They are one of the world's famous flowers, the provincial flower of Yunnan Province, the city flower of Chongqing, Ningbo in Zhejiang Province and other cities, and the prefecture flower of Dali Bai Autonomous Prefecture in Yunnan Province. As early as the Sui and Tang dynasties, the cultivation of Chinese camellia had already entered the imperial court. So how exactly should camellias be grown? Below, let's share the cultivation methods for camellias:

The growing environment for camellias

The suitable growing temperature for camellias is between 15 and 32°C, with a certain temperature difference required, and an environmental humidity above 60%. Most varieties can withstand a low temperature of -8°C (natural overwintering; Yunnan camellias are slightly less cold-tolerant), and in areas south of the Huai River they can generally overwinter naturally. The planting soil for camellias should be on the acidic side and require good air permeability. To favor root hair development, peat, rotted sawdust, red soil, humus soil, or a mixed substrate of the above can usually be used for cultivation. Camellias require stronger light than rhododendrons; in spring, autumn and winter no shading is needed, while in summer 50% shading can be used.

1. Light and temperature: Camellia is a long-day plant. Flower buds can only form in an environment with a day length of 12 hours. The optimum growing temperature is 18-25°C, and the optimum flowering temperature is 10-20°C; above 35°C the leaves will be scorched. It is not cold-tolerant, so in winter it should be brought indoors with the temperature kept at 3-5°C; it can also endure a short period of -10°C, but it must not be kept above 16°C for a long time, otherwise it will be prompted to sprout and cause leaf drop. During the growing period it should be placed in a semi-shaded environment and should not receive overly strong direct sunlight. In particular, shading is needed in summer and autumn, or it can be placed in dappled shade under trees.

2. Watering and fertilizing: Camellias have relatively high requirements for fertilizer and water, and both neutral and alkaline loam soils are unfavorable for their growth. In the north, special attention should be paid to acidifying alkaline water before it can be used to water the flowers. The specific method is to store tap water for 2 days so that the chlorine in the water evaporates, then add an appropriate amount of ferrous sulfate (about 0.5% of the water). The amount of water should not be too large, otherwise the roots are prone to rot. The potting soil must not be dry either, otherwise the roots are prone to shriveling from water loss; it is best to keep the potting soil and the surrounding environment moist. Do not spray water during the flowering period. For fertilizing, thin alum fertilizer water is best, and concentrated fertilizer should be avoided. Generally, after sprouting in spring, apply a thin fertilizer water once every 17 days; in summer apply phosphorus and potassium fertilizers; in early autumn fertilizing can be stopped for about 1 month; before flowering apply alum fertilizer water again, and when flowering apply quick-acting phosphorus and potassium fertilizers, so that the flowers are large and brightly colored with a long flowering period.

Propagation methods for camellias

There are many propagation methods for camellias, and both sexual reproduction and asexual reproduction can be used, among which cuttings and approach grafting are the most commonly used.

1. Cutting propagation: Cutting propagation is the simplest. The most suitable time for cuttings is September, and spring is also acceptable. Choose well-grown, semi-lignified branches, remove the leaves at the base, keep the upper 3 leaves, cut a slanted opening with a sharp knife, immediately soak the cut end in 200-500 ppm indolebutyric acid for 5-15 minutes, dry it in the sun, then insert it into a sand pot or vermiculite pot. After insertion and watering, the wound heals in about 40 days and roots form in about 60 days. Cuttings treated with hormones root 2-3 months earlier than those not treated with hormones. Using vermiculite as the cutting bed also results in much faster rooting than a sand bed.

2. Approach grafting propagation: Choose a suitable variety such as tea-cup camellia or oil tea as the rootstock, and approach-graft a precious camellia onto it. The time for approach grafting is generally between Qingming Festival and Mid-Autumn Festival. First plant the rootstock in a flower pot, use a knife to cut away about half at each of the parts to be joined, with smooth cuts, then make the cut surfaces of both sides fit tightly together, wrap with plastic film, water the rootstock twice a day, and after 60 days it will have healed. At that time it can be cut off and planted, and placed under tree shade to avoid direct sunlight. In February of the following year, use a knife to cut off the tail end of the rootstock, then plant it in its final position.

3. Leaf cutting propagation: For camellia propagation by leaf cutting, branch cuttings are generally used, but for some precious varieties, due to limited sources of branches, or because taking material would affect their tree shape, the leaf cutting method is also used. Use mountain soil as the cutting substrate, and mix in 1/3 river sand to facilitate aeration and drainage. Put the substrate in a clay pot, then carry out pot insertion. Leaf cuttings are best done during the rainy season. Take one-year-old leaves as leaf cutting material; ones that are too old are not easy to root, and ones that are too tender rot easily. Insert about 2 cm into the soil, press the soil firmly after insertion, water thoroughly, then place in a cool and ventilated place. Generally roots can develop in 3 months, and in the spring of the following year they can sprout and send out branches.

4. High-altitude layering propagation: The greatest feature of the high-altitude layering method is that it can give new life to all the weak and small branches on the camellia that would otherwise be pruned off. Moreover, this method has a high survival rate, quick rejuvenation and early flowering. The method is: on the weak and thin branches that need to be pruned off, carry out girdling at an appropriate position (generally 15-25 cm of branch can be left on the upper part). The girdling length can be between 5 and 8 mm. Tie on a suitably sized plastic film, add sterilized and disinfected peat soil or leaf mold inside the film, and after 7-10 days, carry out another girdling of 5-8 mm below the plastic film. This is called the double-girdling high-layering method.

5. Tree grafting propagation: Camellias are plants that are relatively difficult to keep alive. There are many and varied propagation methods for camellias, among which grafting is the most commonly used. Grafting camellias has many advantages: it can maintain the excellent traits of the variety; it can speed up plant growth so that they quickly take shape and can be produced on a large scale; it saves scion material, which is especially important for rare varieties with few sources of scions. The technique for grafting camellias onto oil tea trees is as follows.

① Grafting time: The suitable time for grafting is between June and July. At this time the new shoot leaves of the camellia scion have already unfolded, and the temperature is relatively high, so the grafting wound heals quickly and the survival rate is high.

② Grafting method: Use the cut grafting method among the branch grafting methods. Because the grafting position is relatively high, we often call it “high grafting to replace the head”.

After reading about the growing environment and propagation methods of camellias, next please follow the editor to take a look at the cultivation methods for camellias!