How to Grow Crown of Thorns (Euphorbia milii)? Latest Detailed Potted Care Guide
Crown of Thorns is also known as Jinguangzuan, Iron Begonia, etc. It is a succulent plant of the genus Euphorbia in the family Euphorbiaceae, native to the Americas. Because it closely resembles the qilin of ancient Chinese legend, it is also called Jade Qilin. It gets the name Golden Qilin because at night, when illuminated by light, the thorns on the plant reflect a sparkling golden glow. Now let us take a look at how to grow potted Crown of Thorns!
Growth Habits of Crown of Thorns
The stems of Crown of Thorns are densely covered with brown hard thorns. The leaves are alternate, broadly lanceolate, and very few in number, all growing on new branches. It is native to the cold zones of the Americas. In China, it is cultivated outdoors in provinces such as Guangdong, Guangxi and Yunnan, while in North China and East China it is mostly grown in pots for ornamental enjoyment. It likes full sunlight but also tolerates partial shade, and a slight drought will not kill it.
Propagation Methods for Crown of Thorns
Crown of Thorns is best propagated by cuttings. From May to June, cut 8 cm to 10 cm cuttings from the tips of the mother plant's branches, wipe off the white sap flowing from the cut, dip them in plant ash, and leave them for 3 to 4 days until the wounds dry before inserting them into clean sandy soil. After inserting, water sparingly to keep the potting soil half-dry; roots will form in about 1 month or more. In the second year in autumn, transplant them into flower pots. Normally, water sparingly and water again only after the soil dries, otherwise the roots will rot. In summer, keep the room temperature at around 10°C and they can overwinter safely.
Cultivation Methods for Crown of Thorns
1. Soil: For growing Crown of Thorns, the potting soil is best made from a mixture of a larger amount of pond mud (river mud) and a small amount of coal cinder. This kind of mixed soil has excellent drainage and aeration, which is very beneficial to the growth of Crown of Thorns.
2. Watering: Crown of Thorns likes neutral soil and water. Water and soil that are too acidic or too alkaline will threaten its growth. Since it is a cactus-type plant, water it sparingly, preferably once every 6 to 7 days. When grown outdoors in a sunny spot, it can be watered by spray, once every 2 days. There must be no standing water in the pot, otherwise the roots easily rot. When watering, the water should be brought to room temperature. If the temperature of the water differs too much from the surface temperature of the Crown of Thorns plant, it can easily cause the surface to crack and may even lead to the death of the plant.
3. Light: Crown of Thorns originates from the deserts of South America and likes high temperatures, light and full sun exposure. Plenty of sunlight is more conducive to promoting its growth. Precisely for this reason, balconies and rooftops in the south become their best cultivation sites. In the north, since Crown of Thorns is cold-tolerant and drought-tolerant and easy to keep alive, placing them indoors for growing is also no problem. But if conditions permit, moving them outdoors for full sun exposure on sunny days will make them grow even better.
4. Fertilizing: Crown of Thorns is suited to neutral fertilizers, such as potassium nitrate. Or certain organic fertilizers, such as peanut residue cake or bean dregs cake. It can be fertilized once a month, and during the growth period in May and June, a little more can be applied as appropriate.
5. Pests and Diseases: Crown of Thorns has few pests and diseases, but if kept long-term in a greenhouse or in a poorly ventilated location, it is prone to damage by scale insects. In winter and spring, the leaves can be sprayed and washed with clean water once every 10 days to remove dust. In addition, it is sensitive to sprays, tea and gas.
6. Repotting: When the temperature warms up and rises in spring, the Crown of Thorns can be repotted between Qingming and Guyu. When repotting, remove the old soil, clear away the old soil among the roots, and remove decayed roots. After repotting, keep the potting soil moist, place it indoors for about 10 days first, then gradually move it outdoors.