hydrangea love shade. also some clematis would do well in the conditions she's got in her yard.
ferns do well in shade. hosta's. there's a viney/ground cover that is has yellow leaves - can't think of the name of it right now tho...
there are a large variety of geranium - some do well in shade, all of them
flower (come in reds, whites, pink, purples) and some have variegated leaves - i've got one with yellow/green/white leaves that has a pink
flower. i'll get the name of it for you when i go home tonight.
some peony's do okay in shade - they come in bushes as well as
trees. colors are pinks, reds purples, whites. i think there might even be yellows too.