How to grow the latest potted azaleas?

Rhododendron, also known as rhododendron, Yingshanhong, Zhaoshanhong and so on, is an evergreen or ordinary green shrub of the rhododendron family, with a bright red Corolla. It is a famous flower plant with high ornamental value and is cultivated in parks all over the world. Jiangxi, Anhui and Guizhou take rhododendron as provincial flowers. Let's take a look at how potted rhododendrons are cultivated.

Growth habits of Rhododendron

Rhododendron likes cool, moist and ventilated semi-shady environment, and is afraid of both extreme heat and cold. The suitable temperature for growth is 12 ℃ to 25 ℃. When the summer temperature exceeds 35 ℃, the new shoots and leaves grow slowly and are in a semi-dormant state. Sunscreen should be used in summer and warm and cold in winter. Avoid hot sun exposure, suitable for growth under scattered light with low light intensity, too strong light, young leaves are easy to burn, new leaves and old leaves scorched edge, serious will lead to plant death. In winter, cuckoos cultivated in open field should take measures to prevent cold in order to ensure their safety through the winter.

How to grow potted azaleas?

1. Soil: potted cuckoos should choose acid soil that is loose and rich in humus, and planting rhododendrons should ensure acid soil rich in humus, loose soil, good air permeability and good drainage. Do not use clay or alkaline soil. The pH value of acid soil should be controlled between 5.5 and 6.5.

2. Temperature: potted rhododendrons maintain indoor temperature. there are many varieties of rhododendrons, and the temperature requirements are also different. most rhododendrons like a warm environment, the suitable temperature is between 15 and 28 degrees, and the room temperature in winter is generally not lower than 10 degrees. When the temperature is too high, the rhododendron will stop growing, so it is easy to put it in a cool and ventilated place in summer and indoors in winter. If necessary, the indoor temperature can be increased to prevent frost damage.

3. Watering: potted rhododendrons should be watered during flowering and summer. Rhododendrons already like humid environments. During flowering from April to June, they need to maintain sufficient moisture and should be watered once every evening. When the climate is hot and dry in summer, because there is more evaporation, it should be watered once a day. It can be watered every 4 days in spring and autumn. The cuckoo enters the dormant period in winter, which can reduce the amount of water.

4. Sunshine: potted rhododendrons should not be overexposed, azaleas should not be exposed to the sun, and some shelter should be given when placed in the sun to prevent burns of branches and leaves, but the specific light should also vary with the season, such as spring and autumn, the sun is not strong, give about 20% shelter, if it is flowering and summer, give 60% shelter.

5. Water quality: potted cuckoos are best watered with natural water. Better natural water includes fish tank water, Rain Water, pond water and river water. Usually, some "trapped water" can be stored, that is, the water and the cuckoo are placed at the same temperature for a day or two. In this way, the water can reach the same temperature as the soil and store more nutrients.

6. Fertilization: potted rhododendron should ensure that thin fertilizer is applied frequently, like fertilizer but avoid thick fertilizer, and do not apply more fertilizer each time. In order to promote the growth of its branches and leaves from February to March, light fertilizer based on nitrogen and potassium can be applied every 10 days. The flowering period is from April to June, which should be dominated by phosphate fertilizer and supplemented by potassium fertilizer, which should be fertilized every 5 days. Fertilization should be stopped when the temperature is higher than 28 degrees. Less fertilizer should also be applied in winter. Some alum fertilizer water or a little ferrous sulfate should be added to the water to maintain the acidity of the basin soil.

7. Change pots: potted rhododendrons change their flowerpots in time. When azaleas grow up, they should change their flowerpots in time so as not to affect their growth. Generally, 5-inch pots are suitable for 5-year-old plants, 6-inch pots for 7-and 10-year-old plants, and 8-inch pots for plants over 11 years old. Some slow-release fertilizers should be added properly when changing the basin.

8. Pruning: pruning is an important measure in daily maintenance and management, which can regulate growth and development and make growth exuberant. Daily pruning needs to cut off a small number of diseased branches and weak old branches, combined with the crown shape to delete some overdense branches to increase ventilation and light, which is conducive to plant growth. The cuckoo garden should be inspected frequently, and if dead and diseased branches are found, they should be removed in time to reduce the spread of diseases and insect pests in the cuckoo.

9. Picking buds: potted rhododendrons should pick buds in time to concentrate nutrients and promote flowers. Pruning branches is generally carried out in spring and autumn, cutting off cross branches, over-dense branches, overlapping branches, diseased and weak branches, and remove residual flowers in time. Plastic surgery is generally a natural tree shape with a little artificial modification, at will, because of the tree shape.

Control of diseases and insect pests of rhododendron

1. Brown spot

[symptom] Brown spot is a major disease of rhododendron. At the beginning of the disease, small brown spots appeared on the leaf surface, which gradually developed into irregular spots, and many black or grayish brown spots were produced on the disease spots, which made the damaged leaves yellow and fall off, affecting the flowering of the current year and the development of flower buds in the coming year. This disease often occurs during the rainy season when the humidity is high.

[control] at ordinary times, we should pay attention to make the plant ventilated and transparent, not to make the humidity too high, and increase the application of organic fertilizer and nitrogen, phosphorus and potassium mixed fertilizer to enhance the plant resistance to infection and growth. If diseased leaves are found, they should be removed in time and burned centrally. At the initial stage of the disease, 0.5% Bordeaux solution or 0.4 Baume stone sulfur agent was sprayed, and 4% flour was added to increase the adhesion. Leaf spot and black spot can also be treated with the same method.

2. Chlorosis

[symptoms] Iron deficiency chlorosis often occurs in areas where the soil is alkaline. When the disease is mild, only the plant is late green. In severe cases, the leaf tissue can all turn yellow and the edge of the leaf becomes scorched. When the disease occurs, it is most obvious on the leaves of the top tip of the plant, which is generally caused by internal iron deficiency.

[control] change the property of iron deficiency in soil and reduce soil alkalinity. Apply more organic fertilizer to transform clayey soil. 0.2% ferrous sulfate solution can be directly sprayed on iron-deficient plants. You can also poke several holes about 15 cm deep in the soil around the plant with chopsticks and slowly inject them with liquid ferrous sulfate solution at 1:30 to fill the holes to increase soil acidity and reduce alkalinity.

3. Military worms

[symptoms] the adult body of the military worm is small and flat, about 4 mm long and black. It is the most harmful pest to the evergreen rhododendron. It often sucks leaf sap behind the leaves, and yellow-white spots appear on the leaves of the injured area, causing the leaves to fall off, causing the tree to weaken and affect its growth and flowering. The cuckoo is very prone to this insect in the greenhouse.

[control] it can be sprayed with 1000 times of 90% trichlorfon or 1500 times of 40% omethoate EC or 1000-1500 times of 50% fenitrothion emulsion.

4. Aphids

[symptoms] aphids mainly harm young branches and leaves of rhododendron, light ones can make leaves lose green, heavy ones can make leaves curl, become hard and brittle, can not absorb nutrients and affect flowering.

[control] We should pay special attention to the aphids during the overwintering period. after wintering, we can spray a 5-degree stone-sulfur mixture on the plants to eliminate the overwintering eggs, shovel off the weeds near the flowers and eliminate the insect source. During the period of aphid damage, 40% dimethoate or omethoate was sprayed continuously with 1200 times water, and it was effective after 3 or 4 times.

5. Short Xue'e

[symptom] Scutellaria is one of the most important pests of rhododendron. It often sucks juice near the main vein on the back of the leaf, which forms a lot of oil-stained fields on the back of the leaf, and finally causes the leaf to fall off.

[prevention and control] spray 0.5 degree Baume stone sulfur mixture in mid-late October and early spring respectively to spray 25% insecticidal bloating agent 500 times.

6. Red spider

[symptoms] Red spiders are small in size, but do serious harm to rhododendrons. Cuckoos raised in high-rise buildings are most prone to this kind of pest.

[prevention and control] to carry out manual hunting. Medicine can be used to kill insects with 5 degrees of stone sulfur mixture, or you can use walnut leaves, Yangzhu peach leaves, green poles and other parts to soak out the juice, diluted with water, 11 sprinkles, with 1000 letter water of the dichlorvos solution is also a good way to kill.