Sheri... as the summer wanes on, my verbena is getting leggy, and some of it has that darn white mold! The only thing I can do for that is cut out the moldy areas...
I try really hard to dead head as often as I can - this helps it from getting tooooo leggy too.
Gladys... I don't know how verbena will do in the shade - mine are in all day direct sun.
Sorry I can't help you with shades plants at this time - I don't have any shade gardens right now - but I am putting one in soon, so I'll let you know if I come up with any great flowering plants.