This beautiful and distinctive plant was one of the first Aloes to be successfully cultivated in Europe.
The Afrikaans common name is Kanniedood (cannot die), which may explain why one sees it often planted on graves. It is widely distributed in the dry parts of southern Africa.
The plants prefer stony ground in partial shade (I have never seen a more healthy plant than the one my mother used to grow on her shaded windowsill – and that was in in Holland, not a country known for it abundant sunshine to start with).