Cultivation method of rhododendron (basic knowledge): the best propagation time: the best cutting time of rhododendron is spring (May and) autumn (65438+1October).
Best growing soil: Rhododendron likes acidic soil, but it doesn't grow well or even doesn't grow in calcareous soil. Therefore, soil scientists often regard rhododendron as an indicator crop of acidic soil.
Requirements for growth humidity: Rhododendron likes the environment with high air humidity, but some Rhododendron Gardens are built in squares and roads, and the air flows quickly and is relatively dry. It is necessary to spray water on Rhododendron leaves or the surrounding air frequently to keep the air around Rhododendron Gardens moist.
Optimum growth temperature: the optimum growth temperature of rhododendron is 15 ~ 25℃, and the highest temperature is 32℃. 65438 was moved indoors from mid-June to1mid-October in autumn, and placed in a sunny place in winter. The room temperature should be kept at 5 ~ 10℃, and the lowest temperature should not be lower than 5℃, otherwise the growth will be stopped.
Best growth light: Rhododendron Rhododendron likes cool, humid and ventilated semi-cloudy environment, and is afraid of extreme heat and cold.
Matters needing attention in rhododendron reproduction: fertilization:
(1) Rhododendron has a very thin root system and has a strong ability to absorb water and fertilizer. It likes fertilizer, but it is afraid of thick fertilizer. The excrement of ordinary people is not suitable, and it is suitable for top dressing alum to fertilize water.
(2) Rhododendron fertilization should be carried out according to different growth periods. From March to May, in order to promote the growth of branches and buds, apply fertilizer 1 time per week.
(3) After the azalea blooms in April-May, because the plant consumes a lot of nutrients at the flowering stage, with the germination of leaf buds, new buds are taken out and fertilizer can be applied once every 15 days.
(4) June to August is the summer season. Rhododendron grows slowly and is in a semi-dormant state. Excessive fertilization will not only make the old leaves fall off, but also make the new leaves yellow, and it is also prone to pests and diseases, so fertilization should be stopped.
(5) In late September, the weather gradually turned cold, and azaleas grew in autumn. Applying 20 {BF} ~ 30 {BF} phosphorus-containing liquid fertilizer every 10 day can promote the growth of plant flower buds. After 10 months, the growth in autumn basically stopped, and it was no longer used.
(6) In autumn, some phosphorus and potassium fertilizers can be added, which can be made by adding rice washing water and some peels to the viscera and meat washing water of fish and chicken.
Water supply point:
(1) After planting rhododendron, water it 1 time, so that the root system can fully contact the soil, which is beneficial to the survival and growth of the root system.
(2) Pay attention to watering during the growing period. From March, gradually increase the amount of watering, especially in summer, always keep the basin soil moist, but don't accumulate water. Reduce watering after September, and then water the basin soil after entering the house in winter.
(3) Rhododendron requires soil moisture to be moist, but not moist. Generally, in spring and autumn, the cuckoo planted in the open field can be watered once every 2 ~ 3 days, and in hot summer, it can be watered at least once a day.
(4) Do not use alkaline water for daily watering. You should also pay attention to the water temperature when watering. Especially in hot summer, if drenched with cold water, the soil temperature will suddenly drop, which will affect the water absorption of roots and interfere with the physiological balance of plants.
(5) The watering time should be in the morning and evening, especially in hot summer, not at noon. The principle of watering is not to dry, to water thoroughly, and not to water half.
(6) After10 month, the watering amount should be reduced as appropriate, the water content of branches is low, and the plant tissue is fully developed, which can increase the cold resistance. At this time, keep the basin soil slightly moist.
Pruning essentials: Pruning branches is generally carried out in spring and autumn. Cut off cross branches, over-dense branches, overlapping branches and weak branches, and remove residual flowers in time. Plastic surgery is generally a natural tree, with a little artificial modification, which is arbitrary because of the tree shape.
(1) During daily pruning, a few diseased branches and delicate old branches should be cut off, and some over-dense branches should be removed in combination with crown shape to increase ventilation and light transmission, which is beneficial to plant growth.
(2) Check the cuckoo garden regularly, remove dead branches and diseased branches in time, and reduce the spread of pests and diseases in the cuckoo garden.
Potted soil replacement:
(1) Rhododendron flowerpots are generally turned over after flowering or before autumn buds are pregnant.
(2) When turning over the basin, remove part of the soil and pay attention to pruning the old roots with sharp scissors. Old roots refer to those roots that are blackened and withered due to poor growth.
(3) pay attention. When the seedlings turn over the pots, the roots can't be trimmed. When turning over the pot, you should pay attention to the soil ball at the root. After putting the pot away, you should also pay attention to watering it thoroughly for the first time and let it dry thoroughly in the next few days. If it is too wet, the root incision will rot. Generally, only when new roots grow can normal irrigation be carried out.
(4) In autumn, it is best to turn over the pot in June of 5438+ 10. Although azaleas like to be cool, they should keep warm after turning over the pots in winter. If there is no shed, you can set up a shed in a ventilated place facing south to the sun, covered with plastic film, and spend the winter safely. Generally, the seedlings of Rhododendron in long pots turn once a year, and the big Rhododendron turns 1 time every 2 ~ 3 years.
Breeding point:
1, sowing method: It is best to sow the evergreen rhododendron with harvest, and the deciduous rhododendron can also store the seeds until the next spring sowing. When the temperature is 15 ~ 20℃, the seedlings will emerge in about 20 days.
2. Cutting method: Generally, semi-lignified branches of the current year are selected as cuttings from May to June, and the cuttings are shaded by sheds. They can take root in 65438 0 months at about 25℃. Rhododendron occidentalis takes root slowly, which takes about 60 ~ 70 days.
3. Grafting method: Rhododendron fortunei is widely used for propagation, and the shoots are often split, and the grafting time is not limited. Rootstocks are mostly biennial rhododendrons, and the survival rate is over 90 {BF}.
Pest control:
1. The diseases of rhododendron mainly include root rot, brown spot, black spot, leaf blight and iron deficiency chlorosis.
Root diseases: weak growth, withered leaves, waterlogged palm fields on the surface of root system, serious soft rot, gradual decay and peeling, and black xylem. This disease is most likely to occur in high temperature and high humidity environment. The prevention method is to strictly disinfect Pei 10 soil before turning over the basin, so as to keep the soil loose and moist, make it have good permeability and avoid water accumulation.
Plant diseases: diseased plants and soil must be treated in time. During treatment, the diseased plants can be washed with 0. 1 {BF} potassium permanganate aqueous solution or 2 {BF} ferrous sulfate, then washed with clear water and put on the pot again. Spray 70 {BF} Tobuzin wettable powder with 1000 times of water to make solution, and then it can be cured.
2. The common pests of rhododendron are: red spider, legion worm, aphid, short-bearded snail, etc. Starscream is very small, but it does serious harm to rhododendrons. High-rise buildings with azaleas are most prone to this pest. The control method is artificial killing. Spraying 5% sulfur mixture, or throwing walnut leaves, central bamboo leaves and green bamboo leaves into pieces and soaking them into liquid, diluting them with water, and spraying dichlorvos 1000 letter water are also good insecticidal methods.
Rhododendron breeding experience: 1. The roots of azaleas must be as thin as hair, and there are few thick straight roots. It is afraid of dryness and dampness, especially of heavy fertilizer. If you water too much, the roots will soak in the water and dry too much, the branches and leaves will shrink and fall off, which is a great threat to plants. As for heavy fat, it will be life-threatening.
2. After the flowers wither, the residual flowers must be cut off to avoid consuming nutrition. After the new branches germinate, they should be properly thinned according to the growth of the plants.
3. Rhododendron is most suitable for planting in clay pots, because clay pots absorb water and breathe air, which is beneficial to the growth and development of roots and lush foliage.
4, potted azaleas placed in a specific place, generally should be placed in the southeast of the balcony, and should be ventilated, as little as possible. Without ventilation, it is easy to suffer from black spot disease and a lot of fallen leaves.
5. Rhododendrons should also have moderate requirements for light, and direct light should be avoided in summer. Fertilization should be thin and diligent, and organic compound fertilizer should be applied to the basin soil once a month. Spraying potassium dihydrogen phosphate every 10 day for in vitro fertilization. Add water in time, or add vinegar to the water to increase the acidity.
6, timely sparse buds and leaves, remove some buds that grow too much and too dense, make the air circulate, and concentrate nutrients in the buds. After the bud is formed, it is necessary to increase nutrition and apply more phosphorus and potassium fertilizer, otherwise the bud will become a leaf bud.
7. The main reasons why azalea leaves don't bloom are: too strong direct light in summer, severe cold and frostbite, too much watering, too thick fertilization, too long indoor time, being placed in a dark, humid and unventilated place and being rained by acid rain, so these situations should be avoided in the maintenance process.
8. There is no need to turn over the pots and change the soil every year, usually once every two to three years to minimize the damage to the roots. The time should be after the flowers wither or fall, and topaz should be sprayed at the same time to prevent diseases.
9. The pests of rhododendrons are mainly red spiders and aphids. , you can spray pyrethroids, and the effect is good. If it's not dead after three days, spray it again. The disease is mainly black spot disease, which is caused by hot environment and insufficient light. Measures can be taken to promote air circulation on the one hand and spray Bordeaux mixture and carbendazim on the other.