Asiatics are more hardy than Orientals and generally more vigorous. They bloom earlier. Orientals are not perennial for me in my zone 6, but might return in your zone.

Hope this isn't too late, but I have been growing Casa Blanca for 4-5 years now. Wonderful blooms--much lovelier and shapelier than Asiatic blooms. However, Casa Blanca is not as strong and vigorous as most of my other lilies, although it is the best oriental of the 3 I grow.

If you can find a white orienpet lily, that is a strong, vigorous lily.

I dont' know any white Asiatics, so can't tell you about that, although I do know that Asiatics are supposed to be quite easy to grow. They bloom early in the summer; oriental lilies bloom either mid summer or later summer. Orientpets blooms in between those two types.

Good luck in your search.

Kate

I have an unknown white orienpet lily that blooms in early July and is about 9 feet tall.