Hello John
I love the idea of the ferns i have used this idea before in tropical
Northern Territory Australia and hanging ferns too over the pond i had
orchids too.
If that little nook is just asking for a pond well you go ahead and try
it.
mostly plants will adapt but if you want your lillies to bloom you
really do need the sunshine i can picture it now with all the ferns
there are so many to choose from and like Elaine suggested impatiens
and bergonia (semi florins) for a splash of colour Gold fish will adapt
to the shaded water too.
ok hope i have you fired up let us know how you go.
Regards Pixie Western Australia