The pH value of water for Rhododendron should be below 7. In areas where the water quality tends to be alkaline, in addition to storing rainwater and snow water, acidified water, that is, one hundred pounds of water plus 0.1% ferrous sulfate, can be used for year-round watering. If the acidity is not enough, add a little less vinegar to supplement it. How to water:
(1) Use "trapped water", that is, dry the water and the rhododendron at the same temperature. You can also use fish tank water, rainwater, or river water.
(2) Do not water the soil until it is dry, and do not overdry it, otherwise the leaves will wilt.
(3) Watering must be done thoroughly.
(4) Winter and summer are different. The leaves are fine in winter, but wet spots in summer are okay. It is not advisable to water too much during the flowering period, as too much water will easily cause buds to fall off and fade early; spring and autumn are windy and dry, so adequate watering must be ensured. Pay attention to spraying the leaves and the ground, and maintaining a certain humidity. The amount of fertilizer used for fertilizing azaleas is lighter than that of other flowers. The general rule is: fertilize during the growth period, and do not fertilize during the dormant period; fertilize during the peak period, and do not fertilize for diseased plants; fertilize when the leaf buds are active. You don’t need to fertilize when there is no activity. What kind of fat is good? Acidity and low alkalinity are preferred, requiring moderate fertility, long fertilizer efficiency, and high content of the three elements nitrogen, phosphorus, and potassium. For example, bean cakes, soybeans, sesame paste residue, rice washing water, water chestnut slices, meat washing water, eggs, milk, sheep manure, etc. all contain nitrogen, phosphorus and potassium.
Azalea (Rhododendranspp.), also known as rhododendron and azalea, belongs to the Rhododendron family, Rhododendron family. It is one of the top ten famous flowers in China. Among all ornamental flowers and trees, azaleas are beautiful in both seasons and seasons. They are suitable for both ground planting and potted plants and are extremely versatile.
(1) Morphological characteristics, species and varieties
There are about 900 species of azaleas around the world, with different morphological characteristics formed in different natural environments, including evergreen trees. , small trees, shrubs, and deciduous shrubs. Its basic form is an evergreen or deciduous shrub with many branches, thin and straight branches; leaves are alternate, oblong and oval, with pointed apex, dark green surface and sparse bristles. Racemes, flowers terminal, axillary or solitary, funnel-shaped, with colorful flowers and many varieties. There are currently about 300 horticultural varieties widely cultivated in my country. According to their morphology, traits, parents and sources, they are divided into four types: Eastern cuckoo, hairy cuckoo, western cuckoo and summer cuckoo.
1． Dongjuan is the Eastern cuckoo, because it comes from Japan. Also known as rock azalea, cinnabar azalea, spring azalea, etc. This category includes Rhododendron rhododendron (Rh. obtusum) and its varieties, with many varieties. Its main characteristics are short body size, scattered branches, blooming in April, dense flowering, the smallest flowers, generally 2 cm to 4 cm in diameter, up to 6 cm, single petals or calyx petals formed into sleeve petals, few. It has double petals and a variety of flower colors. Traditional varieties include Xintiandi, Xueyue, Bizhi, Sunrise, and Four Seasons Reputation that can bloom in spring and autumn.
2． Rhododendron is commonly known as hairy-leaf Rhododendron, big-leaf Rhododendron, spring azalea, etc. This category includes Rhododendron pulchrum, Rhododendron mucronatum and their variants and hybrids. They are tall, strong and adaptable, and can be planted in the open field. They are excellent rootstocks for grafting cuckoos. The flowers are large, single-petaled, rarely double-petaled, and the colors include red, purple, pink, white and multiple colors. There are more than 10 varieties, and the most cultivated ones are Jade Butterfly, Purple Butterfly, Sparse Butterfly, etc.
3. The cuckoo was first bred in the Netherlands and Belgium in Western Europe, so it is called the cuckoo, or cuckoo for short. It is a type of Rhododendron (Rh. indicum), azalea and white rhododendron that are repeatedly hybridized. It is the most beautiful type with the most colors and patterns. . Its main characteristics are that it has a short and stocky body, a tight crown, a delicate habit, and is afraid of the sun and frost. The flowering period is from April to May. The flowers are of various colors, mostly double or double petals, and rarely single petals. The flower diameter is 6 cm to 8 cm. Centimeter, traditional varieties include Crown, Jinpao, Tiannvwu, Sihaibo, etc. In recent years, a large number of new hybrid varieties have appeared, and the four-season azalea introduced from abroad is one of them. It is named for its continuous blooming in all seasons and is deeply loved by people.
4. Summer cuckoo is native to India and Japan. In Japan, it is called Satsuki cuckoo (Rhindlcum). It sprouts branches first and blooms the latest, usually from late May to June, hence the name.
The branches and leaves are slender and densely branched, the crown is rich and neat, the leaves are closely arranged, the flower diameter is 6 cm to 8 cm, and the flower colors and petals are as colorful as the azalea. Traditional varieties include Changhua, Dahongpao, Wubao Lvzhu, Zichendian, etc. Among them, there is a small flower in the five-jeweled green pearl flower, which is in the shape of a pavilion. It is the most double-petaled type among azaleas.
(2) Ecological habits and distribution
Rhododendrons are distributed in Europe, Asia and North America, of which my country accounts for about 59% of the world's total, and the original species are concentrated in Yunnan and Tibet It is located in the high mountains of Sichuan with an altitude of 1,000 to 3,000 meters, so it prefers a sparse shade environment, avoids sun exposure, and requires cool and humid climate conditions in summer. The young leaves are easily burned under the hot sun, and the roots are also easily damaged by dry heat. Their cold resistance varies greatly depending on their place of origin, and most have weak cold resistance. Fertile, loose and breathable acidic soil is required, and calcareous alkaline soil and poorly drained clay soil are avoided.
(2) Propagation methods
Sowing, cutting and grafting can be used. Sowing is mostly used to cultivate hybrid seedlings, and cutting and grafting are mostly used for production.
1． Cutting is the most widely used method. It has the advantages of easy operation, high survival rate, rapid growth and stable traits. Cuttings are taken from the newly lignified branches of the current year's young branches, break off the heel, trim the hairs, and cut off the lower leaves, leaving 4 to 5 leaves at the top. If the branches are too long, the top tips can be cut off. If it cannot be picked and inserted at will, the base can be wrapped with wet cloth or moss, covered with plastic film, and placed in a shaded place where it can be stored for several days. The survival rate of cuttings is the highest before the plum rain season. Generally, the West Cuckoo is from late May to early June, the Hair Cuckoo is from early to late June, and the Eastern Cuckoo and Summer Cuckoo are from mid to late June. At this time, the cuttings are moderately old and tender, and the weather is warm and humid. The survival rate can reach more than 90%. The substrate can be peat, decomposed sawdust, orchid mud, Huangshan soil, river sand, perlite, etc. For large-scale production, decomposed sawdust and perlite are often used. The bottom of the inserting bed should be filled with a 7 cm to 8 cm drainage layer to facilitate drainage and the cutting depth. It is 1/3 to 1/2 of the cutting. Rapid soaking treatment with 300PPm naphthaleneacetic acid and 200PPm~300PPm indolebutyric acid can promote rooting. Post-cutting management focuses on shading and spraying water to keep the cuttings fresh. During high-temperature seasons, increase water spraying on the ground and leaves, and pay attention to ventilation and cooling. Hairy cuckoo, eastern cuckoo, and summer cuckoo take root very quickly, about one month, while western cuckoo takes 40 to 70 days. After the roots grow, the top ends and if flower buds form, they should be removed. Reduce shading after September to make the seedlings gradually stronger. Apply light fertilizer in October and pot them in late October.
2． Grafting is often used when propagating cuckoos. Its advantages are: the scion only needs a section of young shoots and can be grafted at any time. It is not limited by time. Several varieties can be grafted on the same plant, which will grow faster than cuttings. The most commonly used grafting method is cleft grafting at the top of young shoots, which is most suitable between May and June. The rootstock should be 2-year-old Trichoderma striata, which requires the new shoots to be similar in thickness to the scion. After grafting, a plastic film bag should be placed at the joint together with the scion. Remove the sleeve and tie the bag tightly. Then place it under a shade shed, avoid direct sunlight, and pay attention to whether there are water drops in the bag. If not, you can untie the spray-wet scion and tie it tightly again. If it does not wilt for 7 days after grafting, you are sure of success. Remove the bag after 2 months and loosen it the following spring.
(4) Cultivation techniques
Evergreen rhododendrons and cultivated varieties such as rhododendron, eastern rhododendron, and summer rhododendron can be grown in pots or on the ground under shade conditions. Only the azalea is delicate and can be grown in pots. Today, the cultivation and management methods of azalea are introduced as follows, and other species can be mastered by reference.
1． On-site cultivation of cuckoo requires two environments: indoor and outdoor: indoor is for winter cold protection, the coldest temperature is not less than -2C--3C, outdoor is for surviving the hot summer. In the Jiangnan area, it is cultivated from mid-April to early November. Outdoors, it is required to have natural shade from deciduous trees, or artificial shade sheds to create a semi-rainy and cool growing environment. The floor should have a drainage slope and the pots should be placed on shelves.
2． When selecting pots for production, use tile pots with good ventilation performance and low prices. Hard plastic basins can also be used in large-scale production, which are beautiful and easy to transport. They are used by large foreign and domestic enterprises. Rhododendrons have shallow roots and slow expansion. Try to use small pots for cultivation to avoid watering out of control and hindering growth.
3. The soil commonly used is black mountain soil, commonly known as orchid mud. You can also use peat soil, Huangshan soil, humus soil, pine needle soil, decomposed sawdust, etc., with a pH of 5 to 6.5, clear drainage, and rich in humus.
4. Potting is usually done when leaving the house in spring or entering the house in autumn. The bottom of the pot is filled with a drainage layer of coarse-grained soil. After potting, place it in a shaded place for a few days before moving it to the appropriate location. During the seedling stage, the pots are repotted more frequently, once every 1 to 2 years. After 10 years, they can be repotted every 3 to 5 years. As long as there are no problems with old trees, they can be repotted for many years.
5. Watering should be flexibly controlled according to weather conditions, plant size, pot soil dryness and moisture, and growth and development needs. The water quality should not be alkaline. If you use tap water to water the flowers, it is best to store them in the tank for 1 to 2 days. The water temperature should be close to the temperature of the pot soil. After November, the temperature drops and the water requirement is small. If the room is not heated, it will not be a problem to go without watering for 3 to 5 days. After late February, the amount of watering should be increased appropriately. From March to June, when the flowers are blooming and sprouting, water needs a lot. Water once a day on sunny days. If insufficient, water should be replenished in the evening. During the plum rain season, if it rains continuously for days, water should be poured into the side basin in time. During the high temperature season from July to August, water should be watered as dry as possible. Water should be sprayed on the ground and leaves at noon and evening to cool down and increase humidity. From September to October, the weather is still hot, so watering should not be neglected.
6. Fertilization of cuckoo requires thin fertilizer and frequent application. Commonly used fertilizers are grass juice water, fishy water, and rapeseed cake. Grass juice is made from young grass and vegetable leaves and can be used as water. For fishy water, add 10 times water to fish offal, etc., and seal and ferment for more than half a year. When applying, add water, and the concentration should be 3% to 5%. This fertilizer is rich in phosphorus, which can make the leaves bright and the flowers colorful, but it should be rinsed with clean water once the next day. Rapeseed cake is a comprehensive fertilizer, which should be retted for several months and then applied with water. For large-scale production of azalea potted flowers, compound fertilizer or slow application fertilizer can be used, and it can be applied 1 to 2 times a year.
7. Sunshade cuckoos need to be shaded from May to November. The height of the shed is 2 meters, the light transmittance of the shade net is 20% to 30%, and curtains should be hung on both sides to block the light.
8． Prune seedlings within 2 to 4 years. In order to speed up the formation of skeletons, the flower buds are often removed and the heads are often pinched to promote the germination of side branches. After they grow into large trees, the main purpose is to prune off diseased branches, weak branches and branches with disordered tree shapes, and thin them out. Cut mainly.
9. Flowering period management and flowering period control: When the azalea is blooming, place it indoors, away from the sun and rain, and it can last for 1 month. If indoor ventilation is poor, it should not be left for a long time and should be replaced in one or two weeks. After the rhododendron flower buds differentiate, they can bloom in about 2 weeks after being moved to a 20C environment, but there are great differences between varieties. Abroad, azaleas that bloom on Christmas must be placed in a greenhouse at 15C in early November after they are moved out of the cold room (3C~4C) to ensure they are on the market during the season. Therefore, with the help of temperature regulation, potted azaleas can be grown in all seasons. open. Plant growth regulators can also be used to promote the formation of flower buds in some varieties. The commonly used ones are Bg and chlormequat. The former is sprayed twice with a 0.15% solution, once a week, or once with a 0.25% concentration. The latter Spray once a week with a concentration of 0.3% and treat twice a day. Treatment with paclobutrazol has better effects, but the residual period is several years and will cause dwarfing of the plant type. Pay attention to the dosage and frequency when using it. About 2 months after spraying, the flower buds will be fully developed. At this time, the plants should be refrigerated to promote the maturity of the flower buds. Rhododendron needs to be refrigerated at a temperature of 10C or slightly lower for at least 4 weeks before cultivation. During the refrigeration period, the plants should be kept moist, not overwatered, and maintained with 12 hours of light every day