How to grow and care for crown of thorns (Euphorbia milii): prune every year for more flowers
SummarySoil: choose sandy soil, can mix in a small amount of organic fertilizer. Watering: water every day in summer; in spring and autumn water thoroughly once the soil is nearly dry; reduce watering in winter. Fertilizing: apply 2-3 times of light fertilizer each spring. Light and temperature: the most suitable temperature is around 20°C. Pruning: proper pruning can make crown of thorns bloom more. Precautions: you can use bamboo strips or sticks to shape it; the white sap secreted after the branches are cut is toxic and must not be eaten; attention should also be paid to preventing and controlling diseases.
Crown of thorns, also called iron begonia, kirin flower, or kirin thorn, is a common household ornamental plant, originally from the island of Madagascar in Africa. Crown of thorns is not cold-tolerant and is drought-tolerant, so it likes a warm, humid environment with plenty of sunlight. Its flowers are small and bright red, opening in spring and winter. Every spring it needs to be repotted and replanted, which can extend the growth life of the crown of thorns.
How to grow crown of thorns
1. Soil requirements
The soil requirement for potted crown of thorns is sandy. You can choose peat soil or leaf mold plus half sand and a small amount of organic fertilizer mixed together to make soil suitable for the growth of crown of thorns. You can also use culture soil with hoof and horn pieces as base fertilizer. The fertilizer must not contain grease, as that will rot the roots of the crown of thorns. During the growing period of the crown of thorns, apply organic fertilizer about once every 15 days, and after the Start of Autumn you can stop fertilizing the crown of thorns.
2. Watering method
Crown of thorns is drought-tolerant and belongs to the succulent group of plants. In summer, because the temperature is high and water evaporates easily, you must water the plant every day, but watering must not cause water to accumulate in the pot. If it remains in a waterlogged state, the roots of the crown of thorns rot easily, and in severe cases the plant will die.
In spring and autumn, water the crown of thorns thoroughly in one go, and wait until it is nearly dry before watering again. In winter, wait until the surface layer of the soil is completely dry before watering. This watering method can give the crown of thorns the water it needs to grow, while also ensuring the oxygen needed for root respiration in the soil, which is good for the robust growth of the crown of thorns. Pay special attention to one point: during the flowering period of the crown of thorns, you must not water too much, otherwise the flower buds of the crown of thorns will fall off, and it can also easily cause root rot.
3. Fertilizing method
Crown of thorns does not need a large amount of fertilizer. Just apply 2-3 times of light fertilizer each spring, and during its growing period just apply one application of fully decomposed, thin cake fertilizer water. In autumn you can reduce fertilizing it. If too much nitrogen fertilizer is applied, it will only grow leaves and not bloom. To make more flower buds and make the flower colors brighter, you can apply phosphorus fertilizer 1-2 times during the bud stage.
4. Light and temperature requirements
The most suitable growing temperature for crown of thorns is around 20°C, and the flowers can keep blooming. If the temperature is below 10°C, it will enter dormancy, all the leaves will fall off, and in the coming year it will grow new leaves and continue to bloom. During this period the soil must be kept dry, but when the temperature is below 0°C the crown of thorns will die because of the cold.
During the flowering period of the crown of thorns, sufficient light can make the flower colors more brilliant and can also lengthen the flowering period. Conversely, insufficient light will make the flower colors darker, and if kept in a shady place for a long time, the crown of thorns will not bloom or will bloom very little.
5. Proper pruning
Properly pruning the flower branches of the crown of thorns can make it bloom more. If the main branches are too long, the amount of flowering will decrease a lot. You should cut short the overly long and uneven flower branches, so that two new flower branches can grow out. You must prune once every year, and after a few years the whole crown of thorns will produce many flowers.
Precautions for crown of thorns
1. Use bamboo strips or sticks as supports to make the crown of thorns more upright. You can also tie the bamboo strips into a shape you like to make it more beautiful.
2. After the branches of the crown of thorns are cut, it secretes a white sap. This sap is toxic and is forbidden to eat.
3. The temperature for the crown of thorns must not be lower than 12°C, otherwise it will affect the quality of flowering.
4. Crown of thorns is prone to stem blight and rot. You can use 50% captan 800-fold solution for protection, spraying once every 15 days. You should also use 50% fenitrothion emulsifiable concentrate 1500-fold solution to protect against whiteflies and scale insects.