When is the best time for camellia oleifera to graft for the highest survival rate
This article brings you the knowledge of when camellia oleifera is best grafted to ensure high survival rates and an understanding of the timing and methods of camellia grafting. It is some very useful gardening tips, recommended for collection!
How to use camellia oleifera as rootstock for grafting 18 Scholars camellia
The 18 Scholars camellia is a famous Chinese flower and the county flower of Dehua County, Fujian Province. It is often used as an ornamental flower to beautify the environment in urban construction in China. Its flowers have many petals, a long blooming period, various and bright colors. It usually takes 4 to 5 years for the plant to start flowering and even longer for the plant to grow to a larger size. Urban construction differs from family ornamental planting; generally, larger camellia seedlings are needed. Due to the long growth cycle, the land utilization rate is low. If the current yield lags behind the urban development demand, increasing the number of seedlings cultivated not only fails to meet market needs in a timely manner but also increases the risk of excessive market supply. Additionally, the existing camellias have a single color and the position of the flowers on the plant cannot be predetermined, making it difficult to拼出 patterns with flower colors, and even the arrangement of the outline is not easy. For this reason, the Dehua 18 Scholars Camellia Technology Cultivation Research Institute in Fujian Province organized technical personnel to tackle the problem, using camellia oleifera as rootstock to graft 18 Scholars camellia, solving the above technical issues and obtaining a national invention patent in December 2017 (Patent No. ZL2014 1 0444697.1). The main technology is introduced as follows.
1 Preparation before grafting
1.1 Grafting site conditions
The grafting site is located in Menghu Village, Chishui Town, Dehua County, which belongs to the subtropical climate zone. The average annual temperature is 16 to 18℃, rainfall is 1,600 mm, and the frost-free period is 250 days. The grafting site is surrounded by green mountains and clear waters, with soil, water sources, and air not polluted. The soil has a high organic matter content, moderate sand and clay, convenient irrigation and drainage, and is suitable for the growth of camellia oleifera and 18 Scholars camellia.
1.2 Rootstock selection
For grafting 18 Scholars camellia onto camellia oleifera, the method of top grafting with camellia oleifera is generally used, selecting 4 to 10-year-old camellia oleifera trees with a trunk height of over 1 meter, a diameter of 2 to 4 cm, vigorous growth, and no diseases or pests as rootstock. Two years ago, they were dug from the camellia forest and transplanted to the nursery in Menghu Village, and grafted after surviving for more than one year. On the rootstock, 5 to 7 main branches with a diameter of 2 to 5 cm are selected as scion branches. The scion branches must have an appropriate angle and be evenly distributed to ensure that the new tree crown is suitable for the camellia, making the flower distribution uniform and beautiful. In addition to the scion branches, 1 to 2 branches should be left on each rootstock as nutritional supply branches. The scion branches are cut to retain 4 to 8 cm, and the excess branches and the central main trunk above the grafting rootstock are removed. The growth of the rootstock should be vigorous, and the collection of scions for grafting can ensure a high survival rate and coordinated growth.
1.3 Scion selection
Select healthy, dark green leaves, pest and disease-free, full buds, and one-year-old branches with a diameter of 0.2 cm or more from the mother tree of 18 Scholars camellia as scions to improve survival rates and coordinate growth. For the same rootstock, scions should be selected from different mother plants with similar flowering times and growth conditions to ensure balanced tree crown development. For rootstocks with a thicker base diameter, scions of 18 Scholars camellia varieties with fast growth and large flower types should be selected; for rootstocks with a thinner base diameter, scions of 18 Scholars camellia varieties with smaller leaves and flower diameters should be selected. Multiple scions of different flower color varieties can be grafted onto the same rootstock to form a colorful and diverse structure with different colors on each side and from top to bottom, greatly enhancing the ornamental value.
2 Grafting techniques
2.1 Grafting time
Grafting camellia oleifera onto 18 Scholars camellia can be done during the growing season of both camellia oleifera and camellia sinensis in spring, summer, and autumn, but the best results are achieved from March to July. During this period, the temperature is relatively suitable, the scion has a longer growing period in the year, the camellia sinensis scion has lignified, and the quality of the scion is good, resulting in a high survival rate of the graft. Although the temperature is relatively suitable and the survival rate is higher from October to November, the scion has a shorter growing period in the year, and the new shoots of the scion have not fully lignified after winter, making them prone to frost damage. It is best to do this in a greenhouse.
2.2 Rootstock cutting
The height of the rootstock is controlled to 50 to 60 cm from the ground, and the branch length is controlled to 2 to 5 cm before cutting. The auxiliary lateral branches are retained, other lateral branches are removed, the debris around the cut is cleared, and the cut surface is flattened, keeping the inner side slightly higher.
2.3 Grafting
The common grafting methods are cut grafting and split grafting. One is the cut grafting method. Cut the scion into 3 to 4 cm sections, ensuring 1 to 2 lateral buds per section, retaining the top 2 leaves, and removing the other leaves. Make a long oblique cut of 1 to 2 cm at 1 cm below the lower bud on the scion, and make a short oblique cut of 0.5 cm on the opposite side of the long oblique cut. Flatten the cut surface of the rootstock branch, select a smooth place at the edge of the xylem of the rootstock cross-section, make a vertical cut downward, and the length and width of the cut should be equivalent to the length and width of the long oblique surface of the scion. Then insert the scion's long oblique surface into the main grafting branch of the rootstock, wrap the cut epidermis around the scion, and tie it with a plastic film strip about 1 cm wide. When tying, the film strip must be pulled tight. The second is the split grafting method. After cutting the rootstock close to the ground, flatten the cross-section and make a vertical cut 1/2 the depth of the cross-section, 5 to 10 cm deep. Cut the scion into sections 5 to 10 cm long, retain 2 leaves at the top, cut the scion into a wedge shape with 2 cuts on the front and back, and then insert the cut scion into the rootstock cut and tie it with plastic film.
3 Post- grafting management
3.1 Humidity control with plastic film
After grafting, cover the scion completely with plastic film to protect from sun and retain moisture. Generally, about 30 days after grafting, when the new shoots of the scion touch the plastic film, cut the covered film. About 1 month after grafting, when the grafting joint between the scion and the rootstock is completely healed, first loosen the tied film and then tie it tightly again. In the autumn, when the weather is cool, remove the film completely. When the new shoots grow to 15 cm, set up a bamboo stake as a支柱 and tie the new shoot to the stake to prevent it from being blown over by the wind and reducing the survival rate.
3.2 Timely branch pulling
After the grafting has taken root, it is necessary to shape the plant appropriately, especially for valuable camellias, considering the tree shape and the position of the branches. In August, one year after the main grafting branches have survived, select the main grafting branches that are 40 to 60 cm long, place a cushion at 1/3 of the length of the main grafting branch from the top, tie a pulling rope at the cushion, apply external force to the pulling rope, and make the main grafting branch form an angle of 55° to 65° with the ground, making the main grafting branch evenly distributed around the trunk and forming an open shape. Before pulling the branch, repeatedly push the branch up with your hand, then rub the branch soft from left to right and up and down, gradually pressing it to the required angle before securing it with the pulling rope. If using wire to bundle and shape, do not apply too much force to break the new branches.
3.3 Re-grafting
After the branches are pulled and shaped, select 3 to 4 new branches or auxiliary branches as rootstock for re-grafting different flower shapes and colors of 18 Scholars camellia scions. When the new scions grow to 40 to 60 cm, pull and shape them again. Repeat the process of re-grafting, pulling branches, and pruning 3 to 4 times to make the overall shape of the tree crown gradually approach the predetermined shape.
4 Matching nursery management techniques
4.1 Water and fertilizer management
After high grafting of camellia oleifera with 18 Scholars camellia, it is important to maintain appropriate moisture at the grafting site to promote the formation of callus tissue. Additionally, the trunk of the grafted tree needs water and fertilizer due to pruning and grafting joint healing. Nitrogen fertilizer should be applied in a timely manner, using a 1% urea solution for irrigation, and combined with irrigation every 20 to 30 days. After the scions have grown, a ring-shaped trench can be opened around each plant to apply a ternary compound fertilizer (nitrogen-phosphorus-potassium = 16:16:16) of 50 to 60 g, every 60 days. At the same time, it is important to clear the ditches for drainage and not to waterlog. In case of drought, water should be applied in a timely manner to promote rapid growth of the plants, increase the leaf area, and enhance photosynthesis.
4.2 Pest and disease control
4.2.1 Pest control The 18 Scholars camellia has few pests, but special attention should be paid to preventing the damage of common pests such as golden龟子, scale insects, and aphids to the new shoots of camellias. In case of severe infestation, first cut the branches where the pests lay eggs and the branches that have been damaged. Pesticides such as 5,000 times the concentration of cypermethrin and 1,000 times the concentration of dimethoate can be continuously sprayed 3 times before and after the occurrence of pest infestation. Scale insects are difficult to control and can cause camellias to contract sooty mold. A 25% solution of phosphamidon in 600 times water can be used, spraying once every 1 to 2 weeks for 3 to 4 times to kill the scale insects. Alternatively, they can be removed with an old toothbrush or bamboo strip. The mature branches of camellias are relatively stable, and there may be leaf-rolling moths in the spring and summer seasons, but generally, there is no significant damage, and it is sufficient to remove the larvae of the leaf-rolling moths directly.
4.2.2 Disease control The main diseases include gray spot disease, sooty mold disease, anthracnose disease, and algae spot disease. In the summer, with high temperature and humidity, special attention should be paid to strengthening management and enhancing the disease resistance of the plants. Once disease symptoms are observed on the branches and leaves, a 70% methyl thiophanate solution (1,000 to 1,500 times) or a 10% benz醚甲环唑 water-dispersible granule formulation (1,000 to 1,500 times) can be sprayed for control, every 7 to 10 days for 2 to 3 times, which can effectively control the disease.
The detailed explanation of when to graft camellia oleifera for the best survival rate and understanding the timing and methods of camellia grafting provided in this article, hoping this article can bring you some help in green plant management!