Euphorbia submammillaris is native to rocky coastal areas of South Africa, favoring sandy and gravelly substrates near sea level. It exhibits a polycarpic, bushy growth habit and is characterized by prominent tubercles, setting it apart from typical cylindrical euphorbias. Cylindrical stems 3-5 cm diameter, conical tubercles arranged spirally; height up to 40 cm. Grey-green coloration, lightening under full sun exposure.
Full direct sun exposure for minimum 6 hours; reduced watering from October to March; substrate with at least 70% draining mineral content; minimum temperature 8°C; avoid waterlogging to prevent root rot.