Does anyone have any ideas for a trailing plant for a really dry window
box?

It's high up on the toilet window sill, so I don't bother watering it.
Atm it has orange flowered aloes and grey echeverias, but I really need
something that will trail down the front. I've tried a trailing sedum
'burro's tail' (can't remember its botanical name) but that didn't
survive the winter.

So I need something succulent, doesn't need full sun (it faces E and
there are trees blocking the sun from S) that can tolerate wet soil and
low temperatures in winter (though obviously there is some heat loss
from the toilet which means it isn't as cold as it would be in the
ground).

I think Euphorbia myrsinites might do, but does anyone have any other
ideas?
--
Kay
"Do not insult the crocodile until you have crossed the river"