echinosum wrote:
After several attempts, and numerous sticks stuck in trenches in the
ground and pots indoors and out, I now have, to my astonishment,
precisely one cutting of my Black Mulberry growing in a pot indoors on
the windowsill. It has one leaf, which is growing from the node nearest
to soil surface. The rest of the stick above it looks fairly dead.
There are a couple of small buds coming from the old wood near the leaf
base, where I am expecting some more growth.

That sounds like my redcurrant cuttings. 2 have grown leaves - one from
the top, one from the bottom!

Having got this far, and with only one, I don't want to mess it up.
What do I do next? When would I transfer it outside and pot it on?

I have zero experience with mulberries, but personally I am going to wait
till my redcurrant is showing signs of root.