Lovely grouping. Do you find the silver is less vigorous than the yellow? I have the yellow and at one time had the silver but it petered out on me. I've also seen a white striped called "Albo"; is that the same as the silver or a different variety? I've never seen the plain green.

The silver one is always the smallest of the three. The least chlorophyl, so the least vigour I guess. It needs excellent drainage, more so than the others. I have had it peter out on me more than once too :-( . They are on a kind of little hill now, with a lower area in front. All are doing very well there, so I have hopes that even the silver one will stay with me. The 'albo' would be short for 'albo marginata' or 'albo variegata'. You also see it as 'argentea marginata' or 'argentea variegata'. White or silver, all the same plant.

What a great post. Thank you.