Many people could identify a rosette of startling white leaves as a Dudleya, looking similar to the echeverias to which they are related. Perhaps not so many grow the plants themselves, but they are well worth a try and not at all difficult.
Dudleyas are found naturally along the western edge of North America, from northern Oregon to the tip of Baja California. Most species are limited to coastal areas and the islands just off the coast, but a few are found as far inland as Arizona and Nevada. At the coast, conditions are generally mild in summer and frost-free in winter, with the dry Mediterranean summers moderated by fogs.
Out of the several dozen species, and a couple of hundred named varieties, only a handful are easy to find in cultivation. They vary from tiny D. greenei ‘nana’ rosettes just a couple of centimetres wide to D. brittonii at 50cm wide. Some are not even white, such as D. viscida with its sticky green leaves. The flowers are carried on branched inflorescences, in colours from dull straw yellow to bright orange and red shades. The flower stalks develop in winter to open in spring, and will last into early summer in the British climate.
The white powdery coating is actually considered a wax. It is extremely reflective, especially of ultraviolet light, an obvious protective trait in its natural habitat. It also coats any droplets of water on the leaves, reducing evaporation and incidentally making quite a mess if you let them get rained on.
Dudleyas are relatively easy to grow, although a couple of species have tuberous roots and you might be able to rot them if you try hard enough. They need good light to develop the most intense white coating, but are dormant in very hot conditions. They will thrive outdoors in summer, although the slightest rain will badly mark the leaves. In a greenhouse they should be kept as cool as possible or they will just shrivel up in summer; alive but not attractive. They are fine with temperatures barely above freezing in winter, and several of the inland mountain species such as D. calcicola are far hardier. Although they are unlikely to rot even in dank conditions, they will etiolate and lose their colour if treated too generously in autumn and winter. Rosettes can be chopped and re-rooted if they become too tall or untidy, or new plants can be easily grown from seed.
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