August 17, 2006

By Claude Townsend, Bexar County Master Gardener

Common Name: Crown of Thorns, Christ Crown, Rosa (Corona) Espinas

Scientific Name: Euphorbia milii (old name – E. splendens)

The Crown of Thorns is a member of the Euphorbiaceae (Spurge family)

History
King Juba 11 (50BC to 19 AD) of Numidia (present day Algeria) was the first person to collect succulent-type Euphorbia. He named the plant after his Greek physician, Euphorbus. The second name, Milii, was taken from Baron Milius, once governor of the island of Bourbon. He was responsible for intr5od;ucing the plant into cultivation in France around 1821.

The common name refers to legend that a crown of thorns was placed on Christ’s head at the crucifixion. The plant we know of as “Crown of Thorns” could have been used, as it was introduced to that area from Madagascar some years before the time of Christ.

Plant Needs
Temperature range: Well above frost
Light: Bright light to full sun
Water: Water often in summer 2 or 3 times a week if plant is in the sun. Water less often if plant is indoors during winter.

Plant Description
The Euphorbia milii is a woody succulent with thorns, ranging in height from a few inches to 6-7 foot tall single stalks or small shrub the size of a soccer ball. Some make a perfect plant for hanging basket because they cascade down.

Flowers range in color from deep red to white to multicolor, and in size they vary from tiny-less than the size of a BB, up to ½ inch. On some of the older types you may find red spots on the leaves. Leaves are found mostly on the tips of the plant where flowers appear either as singles or in pairs. In China, the Crown of Thorns is called “PoySean.” Poy means 8, and Sean means saint. The Chinese believe that if one comes across the plant having eight flowers in a bundle, that person will have good luck.

For many years I have had these plants in my collection and find it is quite easy to propagate from seeds, grafting, or cuttings. I prefer rooted cuttings. It is quick and easy. Take the cuttings from the top portion of the plant, remove most of the leaves, add root tone to the cut ends, and let dry in low light for a couple of days. Next place the cuttings in a 50% mixture of potting mix and sand, and keep damp in a shady spot. In a couple of weeks you will have flowers. Transplant in an area with well-drained soil. If roots stay too wet, they will drop all leaves and die.

As for insects, scale, mealy bugs, and occasionally aphids can be a problem; but most of the time this only occurs on weak or sick plants. To control an insect problem, I use two tablespoons of liquid soap mixed in one quart of water.

Caution: This plant is in the Euphorbia family and is mildly poisonous. It bleeds a white sap that can be irritating to the skin. Some people react as they would when coming in contact with Poison Ivy. Should you accidentally get the sap in your eyes, wash them with running water and see a doctor. ever plant near a fish pond-the exudates from broken roots will kill fish.

For more information about this plant, please contact Claude Townsend at C&E Cactus, 210-655-8959, or e-mail to ctownsend@satx.rr.com.

If your interest is in Cactus and Succulents, you might enjoy attending the 2006 TACSS Annual Fall Seminar –“East Meets West in the Alamo City.” This event will be hosted by the San Antonio Cactus & Xerophyte Society and will be held on Saturday, October 7 and Sunday, October 8 at the Marriott Northwest Hotel. Admission to the seminar is free, but space is limited. You must submit a registration form. Call Ann Black at 1-830-336-4471 for hotel details. You may also e-mail her at annblack@gvtc.com.
All Photos by Claude Townsend
Ref: T. Ombrello-UUC Biology Dept.