the main differences are daigremontiana has offshoots pretty much lining the whole leaf, however those of gastonis bonnieri are rather spaced out and larger. daigremontiana grows to a height of three foot, however krich's kalanchoe has been a low growing type, instead of growing to an impressive height of daigremontiana. these two can be hard to distinguish when young, however you can tell them apart from the almost complete lining of a leaf with offshoots present in daigremontiana and the few but larger and spaced out off shoots present in gastonis bonnieri. one thing you will notice usually on the daigremontiana is that the tiger stripe pattern is present only on the underleaf, however the pattern is present usually on the overleaf of gastonis bonnieri, and gastonis bonnieri also may develop a red tinge of colour. I would love to receive offshoots of gastonis bonnieri, if anyone can point to a good seller based in London, England ideally I would be very thankful, as I would like to make comparisons of growth rate and various proportions between these two.
