– Euphorbia excelsa (2017)

By Lil Giessow (October 2017)

I had a confusing start gathering information on the plant Euphorbia excelsa. Wikipedia did not have an article with that exact name. This made me wonder if I had the correct name.

I found information from Horticopia with this same spelling that put the plant in the family Euphorbiacea (spurge). Aspects of accompanying photos and lack of a detailed description added to my not being comfortable with the accuracy.

Finally, I found an information source new to me: Operation Wildflower (OWF). OWF is a South African association of native plant lovers that works to protect habitat and perform knowledgeable transplanting of native plants when needed.

OWF uses the botanical name of Euphorbia excelsa with a family of Euphorbiacae and other name of Olifants River euphorbia – oliantsriveraboom (Afrikans). Found in South African dry, rocky slopes in summer rainfall areas, it is drought-resistant.

This spiny, succulent tree occasionally can grow to reach 10 meters in height, with a compact, rounded crown of stem tips. Vertical ridges occur on the single erect stem.

Branches form longitudinally on the main stem. The quadrangular young stems curve up in a regular candelabrum fashion. The stems have smooth sides with sharp spines on the four ridges.

The trees have narrowing rings that correspond to regular intervals of seasonal growth. Greenish-yellow flowers form in summer to autumn, followed by a three-lobed capsule of seeds.

I traveled to San Diego at the end of July to visit family. In the photo, you see what we found when visiting the San Diego Botanical Garden, which is actually located in Encinitas, Calif. Our daughter Beth is standing next to a happy Euphorbia excelsa.