The Crown of Thorns: From Holy Land to Houseplant

The porosity of terracotta makes it an obvious choice for potting a crown of thorns plant. As a succulent, crown of thorns requires a container that allows water to evaporate from the soil as quickly as possible. Plastic lacks porosity and will retain moisture longer, risking root rot and plant death.

Crown of thorns enjoys a cozy little pot. Err on the side of caution and choose a container that is no more than 2 inches wider than the plant's root ball. These plants should be repotted every two years in the summer, when they are hardiest. Older plants should be repotted in a container no moer than inch larger than the last, whereas younger plants can stand stand a few extra inches.

Many commercially prepared cactus and succulent mixes are ideal for the needs of your crown of thorns plant. These plants are adaptable but do have preferences. A soil that drains quickly is essential. Look for ingredients like peat moss or sand; these allow water to saturate the roots without soaking.

Given its succulent nature, the crown of thorns can go some time between drinks. These plants will shed their leaves if given too much or too little water — balance is key. Crown of thorns plants should be watered when the top inch of soil is dry. Depending on ambient factors, this translates to roughly once per week.

Indoor temperatures and lighting are ideal for crown of thorn plants. Your plant is happiest when receiving at least four hours of direct light per day, so place in a window with eastern or western sun exposure. These hardy plants can withstand temperatures as low as 60 degrees Fahrenheit and as high as 90 degrees Fahrenheit.

Crown of thorns plants are eager to reproduce. To propagate, locate a healthy stem tip and cut quickly and cleanly with sterile scissors. Always wear gloves when handling cuttings as the sap is a toxic skin irritant. Allow the cutting to dry for a day or two, and then promptly plant in a container of succulent mix. In a month or two, roots and new growth will appear. Treat as normal.

Thanks to its toxic sap and thorny stems, the crown of thorns plant isn't very appealing to common pests when properly cared for. However, over-watering can cause root rot, which will weaken the plant's defenses and make it susceptible to infestation. In such a case, your plant may be plagued by biting insects such as mealybugs and whitefly.

Leaf spot is a bacterial infection of the leaves indicated by brown lesions with yellow rings. Caused by a bacterial infection, leaf spot is tough to treat; prevention is the best measure. Avoid wetting the leaves when watering, but allow enough space and ventilation among plants to keep the humidity down if they do get wet.

Everyone knows fertilizer is key to healthy plants. Crown of thorns will thank you for a consistent feeding schedule. When repotting, apply a full-strength dose of your favorite fertilizer. Bloom booster fertilizers with a higher ratio of phosphorus can also be used. Restrict fertilizer in winter to allow the plant to rest, but apply monthly every other season.

The crown of thorns makes an excellent houseplant for those who live in colder climates, but it can thrive outdoors in warmer areas. Native to the diverse ecosystem of Madagascar, the crown of thorns plant has adapted to living in hot deserts and cool rain forests. In tropical places, crown of thorns often grow wildly as part of the landscapes and even as weeds.