Tomorrow is Good Friday, the day Jesus wore a crown of thorns. In visualizing that painful headpiece, it helps me to think about the sharp spikes on the plant with the same name.
As the scientific name indicates, Euphorbia Milii is first cousin to other Euphorbias, including poinsettias, the wide variety of spurges, and Snow on the Mountain. All these species share common characteristics such as inconspicuous flowers surrounded by showy bracts, and a toxic, thick, milky sap. This latex can not only cause skin irritation, but if it comes in contact with a mucous membrane, extremely painful inflammation can result. Some species’ sap is even carcinogenic.
Crown of Thorns not only has poisonous sap, but it adds 1-inch thorns to its defense. According to the University of Illinois, even honey made from the flowers may be poisonous. Clearly, this is a plant that doesn’t want to be eaten!In spite of its malevolent nature, Crown of Thorns is a popular houseplant. It tolerates the dry air found in many homes during the winter, along with sporadic watering. As an added dividend, you get small but showy bright red “flowers,” especially in winter. Just keep it away from pets and small children.
Like most succulents, Crown of Thorns does best in very bright light and the warm temperatures of its native Madagascar. Lower leaves tend to fall off, especially if the plant dries out, revealing the thorny rope-like stems. If transferred to ever-larger pots, these stems can eventually reach six feet in height.
Common problems include over-watering and over-fertilizing. Like other Euphorbias, Crown of Thorns is adapted to a wet/dry cycle. During active growth, water enough to wet the entire root ball, then let the top inch dry out before watering again. Only fertilize at this time, and then at half-strength. After bloom, lay off the fertilizer and let the soil stay on the dry side for several months while the plant rests.
Propagating new plants is easy. Take cuttings from stems that are getting leggy. (This will also help keep your plant compact.) Let the cut end dry overnight, then poke it into a pot of peat and sand. Keep barely moist. New roots will grow along the buried stem.
Legend has it that this is the actual plant used during the crucifixion. It’s possible, as it had already been introduced to the Middle East by that time, and the long thorny stems are flexible enough to weave together.