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What are the key cultivation techniques for rhododendrons?
1. Site selection and soil preparation: Choose a warm and humid site with not-too-strong light, a cool climate, fertile soil, and humus-rich acidic soil with a pH below 7, or neutral soil with a pH of 5-6, and soil with good drainage and aeration. 2. Propagation methods (1) Seed propagation method: The vast majority of rhododendrons can set seed for collection; only double-flowered varieties do not set seed. Generally, the seed maturity period runs from October to January each year. When the fruit skin turns from green to yellow and then brown, the top of the fruit splits open and the seeds begin to scatter; at this point they must be collected promptly.
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Identification and Control Methods of Rhododendron Flower Rot
Symptoms Rhododendron flower rot only harms the flowers, causing the flowering period to shorten, flowers to droop, and early withering and dropping. After the petals are infected, the diseased parts lose their luster, become water-soaked, soft and discolored, and finally turn brown, rot and blacken; when humid, a gray mold layer grows on the surface, affecting ornamental value. Pathogen and disease pattern This disease is caused by a fungus of the class Hyphomycetes, subphylum Deuteromycotina. The pathogen forms sclerotia on rotten flowers, and the sclerotia fall into the soil with the spent flowers to overwinter. In the flowering period of the following year, conidia are produced, spread by wind and rain or air currents, and when the flowers sprout
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How to prevent and treat root rot in rhododendrons? These methods you need to master
Root rot is a serious threat to rhododendrons. Although its incidence rate is not high, the mortality rate after infection is very high, so the prevention and treatment of root rot must be taken seriously in the cultivation and management of rhododendrons. Root rot is a soil-borne disease caused by Fusarium fungi, mostly occurring at the root and stem parts of rhododendrons, because these parts are often moist with insufficient sunlight, and the Deuteromycetes Fusarium fungi are highly active there. Once they invade the cortex, rot soon follows, with water-soaked brown spots and soft rot appearing on the roots, followed by decay and peeling of the bark, the xylem turning dark brown
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Repotting rhododendrons after flowering has its particularities; only by mastering the method can they survive well
When choosing a pot, select a suitable pot according to the size of the plant, with clay pots being best; generally the pot diameter (inner diameter) should not exceed half the crown diameter. Rhododendrons prefer acidic soil, requiring a pH of 4.25-5.5; without maintaining this acidity, potted rhododendrons are very difficult to keep alive, and the potting soil must be loose, well-draining and rich in humus; never use heavy clay soil. When using soil, it is best to prepare it according to the original root-ball soil of the rhododendron; plants previously grown in pine-needle soil should still use pine-needle soil, which can be mixed with a small amount of decomposed horse manure and bone meal, and
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What are the common pests and diseases of rhododendrons?
Rhododendron black spot disease, also called brown spot disease, is a common and frequently occurring leaf spot disease of rhododendrons. After infection, black spots form on the leaves, which gradually dry up and fall off until the plant dies. The disease mainly affects rhododendron leaves and is caused by infection with the fungus Cercospora rhododendri. The pathogen first appears as several small brown spots; as these spots continually expand, the lesions join together into patches, producing grayish-brown mold mycelium. The affected leaves begin at the petiole, turn from green to brownish-yellow and drop early, and in severe cases this affects the growth and development and ornamental value of the rhododendron. The pathogen overwinters on leaves or diseased plants.
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What are the control methods for red spider mites on rhododendrons?
The female adult is about 0.3 mm long, dark red, nearly oval, with a raised back and 4 pairs of dark red legs; the male adult is 0.25 mm long, wedge-shaped, flat and bright red. It produces multiple generations a year, and the adults overwinter at the base of the plant. They mainly cause damage on the underside of leaves near the midrib close to the petiole. During the high-temperature, low-rainfall, dry weather of June to July, they reproduce quickly, and when their numbers are high, the damaged leaves scorch and drop off. Control methods: manual control - check frequently after April, and if red spider
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How to fertilize rhododendrons? Five key points to note
Rhododendron roots are delicate, so fertilizer must be fully composted before use. Generally, fertilizer that has been composted for more than one year and fully fermented is most suitable. When fertilizing, pay attention to the following five key points: Feed according to the seedling. Seedlings cannot be fertilized; after 4 months, a well-composted, extremely dilute liquid manure may be applied. After the plants are set out and transplanted separately in the following spring, more nitrogen and potassium fertilizer should be applied to speed up vegetative growth. At 2 to 3 years, during the mature stage, more phosphorus fertilizer should be added to achieve a high flowering rate and large, brightly colored flowers. In the old stage, more nitrogen fertilizer may be applied to promote renewal of branches and leaves and rejuvenate the tree
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Detailed Explanation of Fertilizing and Watering Methods for Alpine Rhododendrons
There are many opinions on the issue of fertilizing alpine rhododendrons. Based on our practice in recent years, the traditional Chinese method of concentrated fertilizing should be changed and replaced with "light fertilizer applied frequently," that is, balanced fertilizing with every watering, with special attention to the N:P:K ratio at different growth and development stages, because it has a relatively large impact. Every effort should be made to carefully test and analyze with each watering so as to formulate the most ideal pH value and EC value. We conducted a large number of experiments at different growth stages, for example, making 12 gradients from pH3.8 to 7.1
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Key points of seedling-raising techniques for Japanese white pine, rhododendron and other seedlings
Seedling raising of Japanese white pine, rhododendron, etc. For Japanese white pine, in autumn mix the seeds with coarse sand at 1:5, put the mixture in a flower pot and bury it outdoors in a sunny, well-drained spot, and sow around Qingming Festival. Broadcast sow on the seedbed, cover with 1 cm of sandy loam, and generally the seedlings can emerge completely in two months. If the quantity of seeds is very small, soak the seeds in warm water in spring; after 2-3 days, carefully break open the outer seed coat, sow in pots at 25°C, and seedlings can emerge in about 10 days. For rhododendron, when propagating wild rhododendrons or breeding new hybrid cultivars, the sowing method is often used to raise seedlings. Rhododendron
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Detailed Explanation of Rhododendron Cultivation Techniques and Landscape Application
China has a long history of rhododendron cultivation, with records of artificial cultivation dating back to the Han Dynasty. In the Tang Dynasty, rhododendrons began to be used in private gardens, and because of their graceful plant form and brilliant flower colors, they were deeply loved by people. Rhododendron generally refers to plants of the genus Rhododendron in the family Ericaceae, with about 960 species worldwide. China is the birthplace and distribution center of rhododendrons, with about 542 species, mainly distributed in the Hengduan Mountains area of the three provinces and regions of Southwest China, Yunnan, Tibet and Sichuan. Rhododendrons prefer cool conditions and fear scorching sun,
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