Where did you get the seeds?????
edit: I believe the Adeniums with tap roots come from places with deep groundwater that is replenished in rainy season. Plants like socotranum and arabicum come from places with a rainy season, but no groundwater-- Socotra Island and Arabia are perpetually dry, hey? Obseum come from a belt along the middle of Africa, where is gets very dry, but has enough of a rainy season to replenish ground water reserves, except Mali has had such a terrible drought that animals and people are starving to death. Not in the news, not exciting enough, I guess.