All the way from Walnut Creek, Ruth Bancroft asnwers your questions in a reputable publication, the Contra Costa Times or some such.
Q: I heard that succulents could be grown from a single leaf, which has the ability to sprout roots and grow a new plant. This sounded doubtful to me, but I took a leaf off my aloe plant and put it in soil to see if anything would happen, and it simply dried up.
Is there a secret to making this work?
A: Succulents vary widely in terms of their ability to grow from a leaf. There are many, such as aloes, which will not do this at all.
With other groups, such as echeverias or haworthias, it is sometimes possible to successfully root a leaf…. Certain… leaves will easily root, including sedums and crassulas….
Gasterias and sansevierias are even more eager-to-please, and can be grown even from a piece of a leaf, though they are slow to put out roots as well as to send up new shoots.
We find crassulas and pachyphytums (and pachy hybrids) to be very easy leaf-rooters. As for cutting a leaf into bits and rooting – rex begonias are a classic, but they take more moisture than we care to provide, so we have very little success with growing begonia leaf cuttings ourselves. I’ve never tried to grow the gasterias from leaves, only from offsets, and am surprised to learn they readily grow from even a leaf-piece, since they are closely related to the aloes and haworthias. But that is certainly good news for us. Thank you, Ruth Bancroft.