In the northern part of the coastal Euphorbia caput-medusae distribution, the Namaqualand sandveld (and up to Namibia), it appears as if the plants grow thicker, shorter and possibly fewer stems than those near the Cape.
A few stems to the sides in picture have become old and big, while the top of the central part belatedly produced a bunch of vigorous young stems in a second youth… it’s never too late to try once more if there's something left in the tank (Grenier, 2019; Smith, et al, 2017; iNaturalist).