Euphorbia heptagona by the roadside

Euphorbia heptagona can produce many erect stems over the years. Red or yellow, and later grey spines are found along the stem ridges or ribs. Pockets of soil trapped in niches among rocks on steep road excavation slopes and cliffs are but one of the places that suit just fine, even if it takes other plant species long to join here.

Individual stems may last around an estimated 15 years, while plants can lose and grow stems over its lifetime, which may be twice to four times as long, even longer in cultivation. Factors influencing plant longevity include access to sunlight, moisture availability, drainage, and avoidance of extreme temperatures (iNaturalist; Wikipedia; https://llifle.com).