How to cultivate High quality Rhododendron

Rhododendron, also known as Yingshanhong, is one of the top ten traditional flowers in China. It has a long history of cultivation and is extremely rich in horticultural varieties. Because of its dense branches and leaves, green seasons, various colors and bright colors, the layout of the garden is everywhere. It is suitable for potted plants everywhere and is of great ornamental value.

Reproduction method

The methods of lamination, cutting, grafting and sowing can be used for propagation. It is slow to sow and grow seedlings, and it is generally not used except for cultivating new species.

From April to May, the sturdy branches in the middle of the plant were selected and the ring peeling was carried out at the branch point of 6 cm to 7 cm, with the degree of injury to the xylem. It is pocket-shaped with plastic film, and the bag is filled with culture soil to keep the soil moist. Generally, it can be cut and transplanted from October to November.

Softwood cuttings were carried out from June to July. Select the stout, short Internode branches of the year, cut them into cuttings 3 cm to 5 cm long, leave 2 to 3 leaves at the top, cut them in loose and humus-rich acid soil, keep the temperature 25 ℃ to 30 ℃ after cutting, cover the curtain to shield the sun, and take root after about a month. The seedlings are transplanted in the following spring and will blossom in the third year. The survival rate of this method is quite high.

Artificial pollination is carried out when sowing and flowering to harvest seeds. Evergreen trees are sown in the greenhouse in time, and deciduous trees can be stored and sown in spring. The best sowing soil is the mountain mud of the rhododendron growing place, and it can also be mixed with acid rotten leaf soil and loam. Because the seeds are small, they should be carefully sown on a hotbed or in a flowerpot, keep them for 18 ℃ to 20 ℃, germinate after about half a month, and transplant after 5 to 6 months.

Ramet grafting is mainly used to breed valuable varieties, and the survival rate can reach more than 90%. Generally from April to August, two-year-old crude rhododendron was used as rootstock and split with twigs. It can survive from 40 to 50 days after grafting, and cut off from the mother in about 60 days. Winter moved into the indoor sunny place for maintenance, 1 to 2 years can blossom.

Requirements for soil and containers

Rhododendron is suitable for growing in fertile and loose acidic soil, which requires good drainage, water storage, good ventilation, high humus content, good aggregate structure, rich nutrition, water and fertilizer conservation, and the pH value is between 4.5 and 6.5.The results show that rhododendron is suitable for growing in fertile and loose acidic soil. Rhododendron culture soil can be selected from the forest natural humus soil, can also be prepared by artificial methods. Preparation method: Larix gmelinii 3 parts, rotten leaves or weeds 3 parts, turf soil 4 parts, mix them evenly and pile them together to rot; you can also go to the forest where larch is concentrated and dig the surface larch humus soil as the natural culture soil of rhododendron.

When cultivated in the open field, it is appropriate to choose a slightly higher and slightly inclined place to facilitate drainage; it can also be planted with deep-rooted tree species, which is not only beneficial to the root growth of rhododendron, but also can obtain the shade of tree species. When planting, the seedlings must bring soil, the planting hole should be large, and the bottom and all around should be filled with fertile humus.

Maintenance of upper basin and changing basin

The best time for potting is from September to October (when the temperature is 15 ℃ to 20 ℃), even before the buds sprout in March. Put the semi-shade place on the basin, pour through the water, and keep the soil water content about 30%. If it is too wet, it is easy to cause root rot. When cuckoo leaves sprout, apply thin pancake fertilizer and water every 20 days (fertilizer 5% to 10%, water 95% to 90%); fertilize once every ten days after flowering (fertilizer 20%, water 80%) to promote the growth of new shoots and leaves. Azaleas avoid direct sunlight and sunset in summer. From early summer to early autumn, when the daytime temperature is above 27 ℃ and the night temperature is 18 ℃, a large number of flower buds can be formed.

The root system of rhododendron expands slowly and does not need to change pots year after year. However, in order to prevent the decline of basin soil fertility and the deterioration of soil structure, the basin should be changed every 2 to 3 years. The most suitable time for changing pots is after flowering, that is, from early May to late June, when it is warm and humid, it is the most exuberant period for rhododendron growth, and the injury of some roots during pot change does not affect its growth.

Watering

Cuckoos like to be wet and afraid of drought, but they are not resistant to waterlogging and are particularly sensitive to water. The relative humidity of 60% to 70% should be maintained during the growing period, and the relative humidity can reach about 80% before flowering. Therefore, when cultivating cuckoos, we should pay special attention to controlling moisture and air humidity. Watering with acidic, clean and hygienic river or pond water is better, the principle is to see dry and wet, focus on watering thoroughly. It is necessary to avoid under-watering many times and only wet the topsoil to form "waist water cut-off", so that the lower root system lacks water and affects normal growth, but it should not be watered too much to cause rotten roots.

For newly planted pots or newly changed pots, the cuckoo should be watered thoroughly for the first time, usually twice, sometimes multiple times. In the period of vigorous growth, flowering and budding, it is necessary to appropriately increase the amount of water, but do not sprinkle the water on the flowers, it is generally appropriate to water it once in the morning and evening. Slow growth and winter to keep the soil dry. To judge whether the soil is dry or wet, you should not only look at the surface of the soil layer, but also touch the dry and hard soil with your hands. If you can't lift your fingers, you should water the soil immediately. If it is a potted plant, the dark color of the pot wall means that the basin soil is wet, and if the basin wall is white, it should be watered.

Cuckoos have higher requirements for air humidity, often spraying water to the leaves can increase the air humidity and reduce the temperature. In the high temperature season, the frequency of water spraying should be increased.

Fertilizer application

The root system of cuckoo is whisker root, as thin as hair, so as long as the concentration of fertilizer is slightly inappropriate, it will cause fat injury. In particular, the use of raw fertilizer, excessive fertilization and fertilization in the high temperature dormancy period will cause fertilizer injury.

Master the principle of applying thin fertilizer frequently when fertilizing. Phosphate fertilizer was applied once from March to April in spring, and alum fertilizer and water was applied every 10 days. Alum fertilizer and water can be applied twice a month from May to July, and phosphate fertilizer can be applied every 10 days before flowering for 2 to 3 times in a row. Nitrogen and phosphorus mixed fertilizer should be applied once or twice after flowering.

In the midsummer season, the cuckoo grows slowly and is in a semi-dormant state. In order to prevent the old leaves from falling off and the new leaves yellowing, it is not suitable to apply fertilizer. Enter the second vigorous growth period, to pursue one or two times of phosphate fertilizer-based liquid fertilizer to meet the needs of its growth and pregnancy buds, fertilization interval of about half a month, fertilizer must be rotten, and mixed with water 90%. After each fertilization, it is necessary to irrigate the clear water and loosen the soil in time to facilitate ventilation. Stop fertilizing in winter dormancy and plum rain season.

Pay attention to preventing heat and cold

Rhododendron is afraid of both extreme heat and severe cold. The optimum growth temperature is from 12 ℃ to 25 ℃. When the temperature is more than 30 ℃ or less than 5 ℃, the growth stagnates and enters the dormancy state. Therefore, the cuckoo should be protected from sun and shade in summer and cold and warm in winter.

In summer, in order to prevent direct sunlight, flowerpots can be placed indoors, but because the indoor light is too weak, ventilation and humidity are not enough, sometimes a large number of fallen leaves, so outdoor should be moved at night.

Open field cultivation in winter, the use of film cover at night to prevent cold, to prevent frost damage.

Trim shap

Rhododendron plants are low, sprouting ability is strong, branches are dense, overlapping transverse branches are more, not conducive to ventilation and light, but also affect ornamental. Therefore, the plant needs to be adjusted by pruning in order to maintain the perfect plant shape.

Heart picking is mostly carried out in young plants, and the terminal buds are artificially removed, or a small section of tender shoots are removed to control the plant height and promote the germination of lateral branches. Bud peeling is to control blooming too early and too much, reduce nutrient consumption, peel off part or all of the buds before the Winter Solstice blossoms in autumn, which is beneficial to shoot extraction and tree crown cultivation.

Pruning is generally carried out in spring and autumn, removing withered branches, introverted branches, weak branches, overgrown branches and some overlapping branches. According to the actual growth of the plant type, the cuckoo can be trimmed into umbrella type and pagoda shape.

To cultivate the umbrella type, it is necessary to make the lower trunk with multiple lateral branches and be able to extend in all directions. when modeling, the thick lead wire is first used to make an umbrella-shaped skeleton on the basin, and then the branches are evenly distributed on it and bound with plastic strips. When it blossoms, the flower forms a large bouquet, which is very beautiful and spectacular.

To cultivate the pagoda type, it is necessary to start pruning from the fixed dry time, first reshape the underlying branches, then prune layer by layer upward, and finally make the whole plant shape tower-shaped.

Management after flower fade

Potted cuckoos often stop blooming in the second year, or even wither and die, which is caused by poor management, so it is particularly important to strengthen the management after flowering.

Rhododendron flowers should be gradually placed in a shaded place and often sprayed with water so that they can be exposed to direct sunlight sooner or later. Cut off the residual flowers and the lower old leaves in time after the flower fade, so as to reduce the nutrients consumed due to fruit, promote growth and form new flower buds. After the flower fade, turn the pot and change the soil according to the situation. After changing the pot for 10 days, apply liquid fertilizer every 10 days, with nitrogen fertilizer as the main fertilizer and phosphorus fertilizer as the supplement. After entering November, let it see more sunlight, and pay attention to ventilation, no longer fertilize, basin soil can be kept slightly wet.

The old plants should be pruned and rejuvenated before the new buds sprout in early spring. Leave the branch about 30cm and cut off the upper part. However, it should be noted that it can not be carried out at one time, but can be pruned by stages, and each time choose 1 to 3 short pruning branches, so as not to affect the flower appreciation. Fertilizer and fine management should be applied after pruning to promote the development of flower buds and make them grow normally.