Detailed Explanation of the Key Technical Points for Processing and Utilizing Rhododendrons

I. Harvesting and Processing

Pick the flowers in late spring, the leaves in summer, and the roots in autumn and winter; use them fresh or dry them in the sun for later use.

II. Utilization

Landscaping: Rhododendrons have extremely high ornamental value, displaying a beautiful, dignified, and poised tree form throughout the year; not only are the flowers beautiful, but the leaf color of the whole plant is displayed for a longer period, and the plant's form changes with the seasons. Rhododendron stenophyllum var. tungense from Tibet and Rhododendron neriiflorum from Yunnan have a layer of ice-blue bloom on their leaves, which is very spectacular. Rhododendron coriaceum from Yunnan produces yellow-brown new leaves or shiny white young leaves on silvery-gray young stems in spring, rich in beautiful color. The petals of rhododendrons are like light gauze, with colors rich in variation; in the cutting season, gazing at rhododendrons blooming all over the mountains, in brilliant purples and reds, it is as if dots of rouge have been splashed across the boundless green; from afar, the whole trees are freshly green and just bursting forth, and when a breeze passes, the clusters of abundant flowers seem like countless girls draped in red and colorful garments dancing gracefully. This flower blooms in full glory all over the mountains, luxuriantly spread like brocade, full of poetic and picturesque charm. An ancient poem says, "The rhododendron flower and the bird, how deep their resentful beauty and bright color; one suspects it is the blood in the mouth, dripping into flowers on the branch." Though the flowers endure wind and rain, they remain brilliantly lovely; though the leaves suffer frost and snow, they still stand alone in verdant green. In landscaping, rhododendrons, whether in combinations of flower colors or combinations with other plants, will produce a different atmosphere and a different scenery. For example, large-leaved rhododendrons such as Rhododendron macgregoriae and Rhododendron grande, when planted together with majestic large trees, create a tropical atmosphere. Rhododendron fastigiatum and Rhododendron przewalskii have softer, obliquely narrow and long leaves, with a hazy, restrained mood. Rhododendron morii has a compact plant form; Rhododendron orbiculare and Rhododendron semiorbiculare have densely set leaves and neat, uniform tree forms, exactly the landscape commonly seen in Japanese gardens; on this basis, with shrubs as a backdrop behind, or a grove. In front of Magnolia officinalis trees, loquat-leaf trees, taro trees, apricot trees, peach trees, and so on, rhododendrons are used to form a flower-border garden; along the periphery of the garden, the elegant and quiet lawn is enclosed, forming a secluded rhododendron garden; within the garden, sections are arranged, with rhododendrons as the theme, hedges, foundation plantings, rock-garden flower borders, and so on; because there are many kinds, the range of choices is very wide, making it appear more natural and distinctive than a flowerbed-style rhododendron garden.

In landscaping, consideration should also be given to the fact that rhododendrons of different background colors and varieties with different flowering periods, as well as color combinations, all give people a stimulus. For example, red, purplish red, orange-red, pink, and other colors, although different in color, are all variants based on red, and when gathered together they have a sense of harmony, belonging to the harmony of similar tones, causing mild excitement emotionally and having strong decorative quality. Red-flowered rhododendrons on a large lawn contrast with green, red paired with green, and are especially eye-catching, but the color blocks must not be too large. White rhododendrons can be used to separate two color tones; they should not be planted alone, as that is too monotonous, and mixed planting easily dilutes the color tones of other flowers. Because the varieties differ, they can be suitable for applications in all aspects of landscaping. Rhododendron calycinum from Yunnan, Rhododendron camelliifolium, Rhododendron heliolepis, Rhododendron rubiginosum, and Rhododendron micranthum from Yunnan, and Rhododendron orchidiflorum from Tibet are suitable for use as hedges in landscaping. Rhododendron campylocarpum from Yunnan, Rhododendron purdomii, Rhododendron pronum, and Rhododendron radendum are suitable for use as ground cover. Rhododendron fastigiatum from Sichuan, Rhododendron densifolium from Qinghai, and others are suitable for use as ground cover and also for edge decoration. Rhododendron albiflorum from Tibet, Rhododendron leucaspis, Rhododendron oliganthum from Yunnan, Rhododendron haematodes, Rhododendron calycinum, and Rhododendron hippophaeoides. Rhododendron yakuinsulare from the former Soviet Union and Rhododendron mucronulatum from North China are suitable for foundation planting in landscaping.

Food use: The roots and flowers of rhododendrons are both edible. Fresh or dried rhododendron flowers soaked in liquor for 24-48 h are ready to drink. Rhododendron flowers made into soup are fresh-tasting and delicious. Preparation method: split two pig trotters into two halves, blanch them in boiling water, wash them clean in clear water, cut scallions and ginger into sections and slices, put them all into chicken broth and boil over high heat, add soy sauce, cooking wine, salt, and white sugar, and after boiling, simmer over low heat. Wash the rhododendrons clean, remove the stems, and when the pig trotters are tender, add the rhododendrons cut into thick shreds, stirring while adding, then add monosodium glutamate to adjust the taste, and it is ready.

Medicinal applications: Rhododendron root is sour, astringent, warm, and toxic. It dispels wind-dampness, invigorates blood and removes blood stasis, and stops bleeding. The leaves and flowers are sweet, sour, and neutral. They clear heat and remove toxins, resolve phlegm and stop cough, and relieve itching. Rhododendrons contain anthocyanins, cyanidin-3-glucoside, 3,5-diglucoside, with both pigments present at the same time. They also contain flavonols: rhododendrin-3-rhamnoglucoside; the leaves contain dihydroflavonoids, struthiopterin, and so on. The roots contain tannins. The leaves have a very good cough-suppressing effect; 50 g of rhododendron leaves, 100 g of Ficus hirta, 40 g of Houttuynia cordata, 25 g of Elaeagnus leaves, and 15 g of Inula cappa, soaked in 3 bowls of warm water for 30 min, then simmered over low heat for 40 min, leaving one bowl of water, taken in 2 doses, with 10 days as one course of treatment.