How to Grow Potted Azaleas: Cultivation Methods and Precautions

Growing Techniques Jan 1, 1970 0 views

Azalea, also known as yingshanhong or pomegranate flower, is an evergreen or semi-evergreen shrub that generally blooms in spring, with abundant and gorgeous flower colors. Azaleas have always been a popular flower that many people have grown, but many may not be very clear about the cultivation methods and precautions for azaleas.

Growing Conditions

Azaleas grow in sparse mountain shrublands or under pine forests at altitudes of 500-2500 m. They prefer acidic soil and grow poorly or even not at all in calcareous soil. Therefore, soil scientists often use azaleas as an indicator plant for acidic soil.

Azaleas prefer a cool, humid, well-ventilated, semi-shaded environment. They fear both intense heat and severe cold. The suitable growing temperature is 12°C to 25°C. When summer temperatures exceed 35°C, new shoots and new leaves grow slowly, and the plant enters a semi-dormant state. In summer, protect them from sun and provide shade; in winter, pay attention to keeping them warm and protecting them from the cold.

Avoid direct exposure to blazing sun. They are suitable for growing under diffused light of low intensity. If light is too strong, tender leaves are easily scorched, and the edges of new and old leaves burn, which in severe cases can lead to plant death. In winter, field-grown azaleas need measures to protect against cold so they can safely overwinter. Among ornamental azaleas, Western azaleas have the weakest cold resistance, and frost damage easily occurs when the temperature drops below 0°C.

Potting Soil Requirements

Azaleas prefer loose, highly permeable, well-drained acidic soil rich in humus, with a pH of 5.0—6.0. If clay or alkaline soil is used, hardly one in a hundred will survive. In particular, summer azaleas and foreign azaleas must have mountain soil. Mountain soil also needs to be improved. At present, 3 types of prepared culture soil are usually used:

1. Mix 7 parts mountain soil, 1 part dried moss grass debris, 2 parts dry leaf mold, and 1 part dry fertilizer.

2. Layer 3 parts mountain surface soil (topsoil), 3 parts horse manure, 3 parts fallen leaves and weeds, and 1 part human feces and urine for composting. After 1—2 years, sift and set aside for use.

3. Mix 3 parts mountain soil, 3 parts leaf mold, 4 parts garden soil, and 2 parts sandy soil, and add 50 grams of sesame paste residue and bone meal to each pot.

Flower Pot Selection

For pots used to grow azaleas, depending on the purpose, generally two types are chosen: clay pots and purple clay pots. Clay pots have good air and water permeability, which is beneficial to root growth, and production units all use this kind of pot for cultivation. For mature azaleas, especially those already shaped, for indoor and outdoor display, they are generally planted in beautiful and elegant purple clay pots. Purple clay pots are fine in texture, rich in color, and beautiful in shape, which can double their ornamental value. Purple clay pots are less permeable than clay pots, so when planting, broken tiles (old tiles) should be placed around the inner walls of the pot to help drainage.

The size of the selected pot depends on the age of the plant. Generally, 4—6-year-old plants use 5-inch pots, 7—10-year-old plants use 6-inch pots, 11—15-year-old plants use 8-inch pots, and so on.

Fertilizer and Water Management

For watering azaleas, rainwater is best, followed by river water or pond water. If tap water is used, it is advisable to store the water for 1—2 days to let the chlorine evaporate before use. Note to add 0.2% ferrous sulfate when using it. During the growing season, water once every 7—10 days. Use it regularly to ensure the soil is acidic. Azaleas prefer shade and moisture and should not be too dry. During the flowering period, even more water is needed.

① In winter, azaleas have entered the dormant period and do not need much water. Generally, water once every 4—5 days, preferably around noon on a sunny and warm day. The specific amount can be adjusted according to how dry the potting soil is.

② In March, azaleas take root and sprout, and water demand increases accordingly. Summer azaleas grow and develop slightly later, so the amount of watering should be less than for spring azaleas. Generally, water appropriately once every 2 days in the morning.

③ From April to June, azaleas bloom one after another, and branches and leaves also begin to sprout, so water demand is relatively high. Generally, water once every morning or evening.

④ From July to early September, during the hot and dry season, water once in the morning and once in the evening. The amount should not be too much, and at noon spray water on the leaves and ground to maintain a humid environment.

⑤ From mid-September to November, the weather gradually turns cooler, which is the adaptation period for azalea growth. To prevent autumn shoots from sprouting and enhance cold resistance for overwintering, the amount of watering should be appropriately reduced. Generally, water once every other morning, keeping it moist. Azaleas relatively prefer fertilizer. Generally, decomposed cake fertilizer, fish meal, broad bean, or Chinese milk vetch, etc., after rotting, are mixed with water and used for irrigation. Human feces and urine should be avoided. After being moved outdoors until before the flower buds open, apply a thin fertilizer once every 10 days at a concentration of 15%, for a total of 2—3 times, to promote the old leaves turning green and new roots sprouting. After the flowers fade, in order to promote branch and leaf growth, fertilize 5—6 times from mid-May to early July. If it rains continuously, dry fertilizer can be applied. Before moving indoors, before azalea growth is about to stop, fertilize 1—2 times.

Outdoor Shading

1. Before moving outdoors and before flowering, it is appropriate to provide more sunlight.

2. During the flowering period, shade briefly at noon, with a light transmission rate of 60%.

3. During the plum rain period from June to early July, which is exactly the period when azaleas sprout leaves and branches, they should receive as much sunlight as possible. But in strong sunlight, shade should still be provided from 9 a.m. to 4 p.m. to prevent scorching new leaves.

4. From mid-July to early September, shade every day from 8 a.m. to 5 p.m. to prevent blazing sunlight.

5. In the autumn growing period after September, the shading time can be shortened. Generally, shade from 10 a.m. to 4 p.m.

6. After October, it is appropriate to provide more sunlight.

Shaping and Pruning

Azaleas grow relatively slowly. Generally, let them grow naturally and only shape them after flowering, cutting off leggy branches, diseased and weak branches, deformed branches, and damaged branches.

That basically completes the introduction to azalea cultivation methods. Next, let us look at the pest and disease control methods and precautions during azalea cultivation!

Cultivation Methods and Precautions for Home Potted Azaleas

Azalea, also known as shanzhizhu, pomegranate flower, or yingshanhong, is a deciduous shrub in the Ericaceae family. There are about 900 species of azaleas worldwide, and China is the country with the greatest distribution of azaleas, with about 530 species. Azaleas are diverse, with brilliant flower colors and both beautiful flowers and leaves. They are suitable for both ground planting and potting and are one of China's ten traditional famous flowers.

Soil Requirements

To make azaleas bloom beautifully, first become familiar with the soil of their growing environment, with a pH between 5.5 and 6.5. Avoid alkaline or sticky soil. The suitable growing temperature is 12°C to 25°C. In summer, provide shade and sun protection; in winter, protect against freezing and keep warm, preferably moving them indoors. According to the details introduced above, with careful cultivation, azaleas will certainly bloom very beautifully. Azaleas like fertile soil. Acidic humus soil formed from dead branches and fallen leaves piled up and rotted over many years is most suitable for cultivating azaleas. Clay has poor permeability and poor drainage, so it should not be used. In particular, soil containing lime must never be used.

Fertilization Methods

When topdressing, do not apply alkaline fertilizer water. Burying rancid fats such as lard into the soil can make azaleas grow vigorously, bloom more, and produce brightly colored flowers. Correctly use nitrogen, phosphorus, and potassium fertilizers. With sufficient nitrogen fertilizer, leaves are dark green and growth is vigorous. With insufficient nitrogen fertilizer, leaf color is pale and lusterless, leaves are thin and aged-looking, branches are short, small, and weak, and flowers are few and small. Too much nitrogen fertilizer, however, can cause leggy growth. With sufficient phosphorus fertilizer, plants are strong, bear many flowers, and the flower colors are brilliant. With insufficient phosphorus, there are few branches and they are weak, petals are thin, and the flowering period is short. When potassium fertilizer is lacking, azalea branches are slender and the tissues are soft. For young trees, apply appropriately more nitrogen and potassium fertilizer; for mature trees, apply more phosphorus fertilizer. If the soil has already become alkaline, causing leaves to lose green and turn yellow-white, extra ferrous sulfate should be applied. Fertilizer water should not be too concentrated. Apply thin fertilizer frequently. Liquid fertilizer that is too concentrated will scorch the root system and harm the plant.

Water Requirements

1. Azaleas fear both dryness and waterlogging. If the potting soil is too dry, the root tips shrink. First the leaves droop or curl, and later the tips of tender leaves turn scorched yellow. In severe cases, they cannot recover for a long time and gradually wither and die. If the potting soil is too wet, aeration is poor, causing root rot. In mild cases, leaves turn yellow and fall early, and growth stalls; in severe cases, the plant dies.

2. If azalea potting soil is too dry and causes root damage, the remedy is to soak the whole pot and roots in water, place it in a cool place, and spray the leaves several times. If excessive moisture causes yellow leaves and early leaf drop, place the affected plant in a ventilated place, control the frequency and amount of watering, and stop fertilizing to prevent pest and disease infection.

3. Azaleas like a humid environment, so water should often be sprinkled around the pot and on the leaf surfaces to keep the surrounding environment moist. If the surrounding environment is dry, azaleas are very prone to disease. The remedy is to place the diseased azalea in a pit under grapevines or similar trees, cover it with glass, spray water frequently in the pit, and allow slanted light to pass through the grape branches and leaves. The diseased plant will slowly return to normal.

Light Management

After azaleas form buds, they need more sun, but during the flowering period be careful to avoid direct strong light. Strong light will fade the flower color and make the flowers wither early. Diffused light is required, and good ventilation is also required.

Precautions

1. Azalea roots are as fine as hair strands, with few thick main roots. They fear both dryness and moisture, and especially fear heavy fertilizer. If watered too much, the roots soak in water; if too dry, branches and leaves shrink and leaf petals fall off, posing a great threat to the plant. As for applying heavy fertilizer, it can endanger their lives.

2. After the flowers fade, the remaining flowers must be cut off to avoid seed production consuming nutrients. After new branches sprout, thin the branches appropriately, deciding what to keep according to the plant's growth.

3. Azaleas are most suitable for planting in clay pots, because clay pots absorb water and breathe, which is beneficial to root growth and development and lush branches and leaves.

4. The placement of potted azaleas is particular. Generally, they should be placed on a southeast-facing balcony, and they need ventilation, moving them as little as possible. Without ventilation, they are prone to black spot disease and massive leaf drop.

5. Azaleas also have moderate light requirements. Avoid direct light in summer. For fertilization, master the principle of thin fertilizer applied frequently; rather light than concentrated. Apply an organic compound fertilizer to the potting soil once a month. Spray potassium dihydrogen phosphate once every 10 days as foliar feeding. Water in a timely manner, and edible vinegar can also be added to the water to increase acidity.

6. Thin buds and leaves in a timely manner, removing part of the flower buds and leaves that have grown too many and too densely, so that air can circulate and nutrients concentrate in the flower buds. After the flower buds form, increase nutrition and apply an appropriate amount of extra phosphorus and potassium fertilizer, otherwise the flower buds will turn into leaf buds.

7. The main reasons for azalea leaf drop and failure to bloom are: too strong direct sunlight in summer, freezing damage from severe cold, too much watering, too concentrated fertilizing, being kept indoors for too long, being placed in a place with poor air circulation or a dark, damp place, exposure to acid rain, etc. Therefore, these situations should be avoided during care.

8. Repotting and changing soil do not need to be done every year, generally once every 2 to 3 years. Minimize damage to the roots. The time should be after the flowers fade or in autumn, and at the same time spray thiophanate to prevent disease.

9. The main pests of azaleas are red spiders, aphids, etc., which can be sprayed with fenvalerate and similar insecticides for a relatively good effect. If they are not dead after three days, spray again. The main disease is black spot disease, caused by a stuffy, hot environment and lack of light. Measures can be taken to promote air circulation on the one hand and spray Bordeaux mixture or carbendazim on the other.

10. The main propagation method for azaleas is cuttings. Around Grain in Ear, choose new branches 5 cm to 10 cm long, cut them off at the branching point, strip off the lower leaves, keep 3 to 4 top leaves, insert 1/3 of the branch into the soil, spray enough water, and cover with plastic film. Strengthen management at ordinary times, and transplant after one year.

Cultivation Methods and Precautions for Potted Azaleas

Azalea is one of China's ten famous flowers and has always been a popular flower. So how many people know how to grow potted azaleas? Next, let us take a look together!

Growing Conditions for Potted Azaleas

1. Environmental conditions: It is best to have both indoor and outdoor environments for cultivating azaleas. The indoor environment is used in winter. In the Yangtze River basin, as long as there is a certain amount of light and ventilation indoors, generally no heating is needed. In the north, winters are extremely cold and dry, so cultivation in a moderate-temperature (around 15°C) greenhouse is preferable. Outdoor sites are used in summer and autumn, preferably with mud ground; cement ground should be avoided. The site should be spacious, ventilated, and shaded. A shade shed should be built above, covered with reed curtains or using natural tree shade as shelter, with a light transmission rate of about 30%, and absolutely avoid afternoon sun.

2. Potting soil requirements: Azaleas prefer loose, highly permeable, well-drained acidic soil rich in humus, with a pH of 5.0—6.0. If clay or alkaline soil is used, hardly one in a hundred will survive. In particular, summer azaleas and foreign azaleas must have mountain soil. Mountain soil also needs to be improved. At present, 3 types of prepared culture soil are usually used. (1) Mix 7 parts mountain soil, 1 part dried moss grass debris, 2 parts dry leaf mold, and 1 part dry fertilizer. (2) Layer 3 parts mountain surface soil (topsoil), 3 parts horse manure, 3 parts fallen leaves and weeds, and 1 part human feces and urine for composting. After 1—2 years, sift and set aside for use. (3) Mix 3 parts mountain soil, 3 parts leaf mold, 4 parts garden soil, and 2 parts sandy soil, and add 50 grams of sesame paste residue and bone meal to each pot.

3. Flower pot selection: For pots used to cultivate azaleas, depending on the purpose, generally two types are chosen: clay pots and purple clay pots. Clay pots have good air and water permeability, which is beneficial to root growth, and production units all use this kind of pot for cultivation. For mature azaleas, especially those already shaped, for indoor and outdoor display, they are generally planted in beautiful and elegant purple clay pots. Purple clay pots are fine in texture, rich in color, and beautiful in shape, which can double their ornamental value. Purple clay pots are less permeable than clay pots, so when planting, broken tiles (old tiles) should be placed around the inner walls of the pot to help drainage. The size of the selected pot depends on the age of the plant. Generally, 4—6-year-old plants use 5-inch pots; 7—10-year-old plants use 6-inch pots; 11—15-year-old plants use 8-inch pots.

Cultivation Methods for Potted Azaleas

1. Potting soil: For pots, clay pots are more suitable; use ones with holes at the bottom and good ventilation. Since azaleas have shallow roots and grow slowly, smaller pots can be chosen, so water will not be wasted when watering and growth will be better. For the potting soil, use acidic soil that is relatively loose and well drained. Some leaf mold and sawdust can also be used. When filling the pot with soil, note that coarse soil should be used at the bottom layer and fine soil on top. As for renewing the potting soil, newly planted ones can be done once every 1 to 2 years; for those grown for more than 10 years, it can be changed once every 3 to 5 years, or not changed at all.

2. Watering: Azalea roots are very fine and have relatively poor absorption capacity, and water must be absorbed through the roots to reach the flower body. Therefore, when watering azaleas, except during the winter dormant period, watering should be done frequently to keep them moist. Especially in the growing period after March each year, the flowering period, and the high-temperature period from July to September, the frequency of watering should be increased, preferably ensuring watering about twice a day. In autumn and winter, watering can be appropriately reduced. Note that tap water used for watering flowers is best stored in a container for one to two days before use.

3. Light: During azalea cultivation, ensure sufficient light at all times, because only with sufficient light can they bloom well. Of course, in hot summer they cannot be taken out for direct sun exposure; instead, shading work should be strengthened to prevent sun damage. In addition, during the flowering season, appropriate protection should also be provided, and a shade net can be used for protection. They also cannot be exposed to direct sun during the flowering period.

4. Fertilizing: Proper fertilizing can make azaleas grow more robustly and quickly. As with most indoor flower cultivation, the fertilizing principle for azaleas is also thin fertilizer applied more frequently, that is, apply a little less at a time and apply it several times. When old leaves turn green, during the flowering period, and after flowering, apply fertilizer appropriately two to three times. During hot, high-temperature weather, fertilizer must not be applied. For azalea cultivation, fertilizers such as grass juice water, fishy water, and rapeseed cake can be used. In addition, if diseased or weak branches are found, cut them off in time to prevent them from affecting the healthy growth of other branches.

5. Pest control: During azalea cultivation, the main pests include the azalea lace bug, aphids, etc. When pests are found, if there are few and they are visible to the naked eye, they can be wiped off with a wet cloth strip. If there are many and the pest problem is severe, buy insecticide liquid from a local pharmacy for effective control, and make sure to place the azalea pot in a ventilated location with good light. Placing it in a dark place is also one of the causes of pest problems.

Precautions for Growing Potted Azaleas