How to grow rhododendrons? Detailed introduction to cultivation methods
Rhododendron, also known as shan zhizhu, shan shiliu, or yingshanhong, is a deciduous shrub of the family Ericaceae. There are about 900 species of rhododendrons worldwide, and China is the country with the most rhododendron distribution, with about 530 species. Rhododendrons are diverse in variety, brilliant in flower color, and beautiful in both flower and leaf, suitable for both ground planting and pot cultivation, and are one of China's ten traditional famous flowers.
Soil requirements
To make rhododendrons bloom beautifully, you must first be familiar with the soil of their growing environment, with a pH value between 5.5 and 6.5, and avoid alkaline or clayey soil. The suitable growing temperature is 12°C to 25°C. In summer, shade them from the sun, and in winter, protect them from freezing and keep them warm, preferably moving them indoors. Following the details introduced above and cultivating them carefully, rhododendrons will surely bloom very beautifully. Rhododendrons like rich soil. Acidic humus soil formed by piling up and decomposing dead branches and fallen leaves over many years is most suitable for cultivating rhododendrons. Clay has poor permeability and poor drainage, so it should not be used, especially soil containing lime, which must never be used.
Fertilization methods
When applying supplemental fertilizer, do not apply alkaline fertilizer water. Burying rancid fats such as lard into the soil can make rhododendrons grow vigorously, bloom more, and have bright flower colors. Use nitrogen, phosphorus, and potassium fertilizers correctly. With sufficient nitrogen fertilizer, the leaves are deep green and growth is vigorous. With insufficient nitrogen fertilizer, the leaf color is pale and lusterless, the leaves are thin and aged-looking, the branches are short, small, and weak, and the flowers are few and small; excessive nitrogen fertilizer, in turn, causes excessive vegetative growth. With sufficient phosphorus fertilizer, the plant is strong, bears many flowers, and the flower colors are gorgeous. With insufficient phosphorus, there are few branches and they are weak, the petals are thin, and the flowering period is short. When potassium fertilizer is lacking, rhododendron branches are slender and the tissues are soft. When young, apply somewhat more nitrogen and potassium fertilizer; when mature, apply somewhat more phosphorus fertilizer. If the soil has already become alkaline, causing leaf chlorosis and yellow-white discoloration, additional ferrous sulfate should be applied. Fertilizer water should not be too concentrated. Apply light fertilizer frequently. Liquid fertilizer that is too concentrated will burn the root system and harm the plant.
Water requirements
1. Rhododendrons fear both dryness and waterlogging. If the potting soil of a rhododendron is too dry, the root tips shrivel, first the leaves droop or curl, and later the tips of the young 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, the leaves turn yellow and fall early, and growth stalls; in severe cases, the plant dies.
2. If the rhododendron's 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 water on the leaf surface several times. If excessive moisture causes yellow leaves to fall early, place the affected plant in a ventilated place, control the frequency and amount of watering, and stop fertilizing to prevent infection by pests and diseases.
3. Rhododendrons like a humid environment, so water should often be sprinkled around the pot and on the leaf surface to keep the surrounding environment moist. If the surrounding environment is dry, rhododendrons are very susceptible to disease. The remedy is to place the diseased rhododendron in a pit under grapevines or similar trees, cover it well with glass, spray water frequently in the pit, and since slanted light can shine through the grape branches and leaves, the diseased flower will gradually return to normal.