Many succulents are covered in a powder or bloom, in some cases it is thick enough to change the colour of the plant to pale blue or white. Often these are the more sort after varieties and it I find that the plants visitors ask about are the white/blue ones. Here are a few of my white echeverias:
I get the most requests for echeveria john catlin (back right above) which is a very pale blue / white and has probably the heaviest bloom.
Personally while this is one of the palest varieties it can be a bit scruffy and I prefer echeveria cante (top and bottom left in the first photo).
It is a more delicate plant and has good pink tinge to the edge of the leaves. It also has the most amazing flowers of any echeveria and I have shown this photo before.
It is not just the echeverias who dress up, the agaves like to get in on the act as well. One of the best is agave ovatifolia and as is becoming more common someone has taken a particularly white plant and tissue cultured it to sell under the name ovatifolia 'frosty blue'.
With some of these named varieties it is marginal if there is any difference, but if you want the best colour many people feel it is worth going for this variety to ensure you get what you want. Another good named variety is agave mitis var albidor:
It is not as white as the frosty blue, but it is more obviously different from the normal form of agave mitis. Out of all the named forms of agaves this is one I would highly recommend. Sadly as it is still rare in the UK, and you never know how the variation will effect hardiness, I over winter this one in a cold frame. Thankfully the bloom does not seem to wash off in rain, not that we have had any so far this year.
I have mentioned before that you have to watch people around these plants as they have a tendency to touch. There is probably a look of panic on my face when those little hands reach out to touch. Apparently it is not polite to slap guests hands away from your plants. So at least in the plant world blondes seem to get more attention.