Integration Design Studio, Landscape Architects According to Sunset Western Garden Book, the Liriope 'Gigantea' will grow in Seattle. Alphonse Karr Bamboo is hardy to 15 degrees. The Black Bamboo--Phyllostachys nigra can be a bit sparse on foliage but can have aggressive running roots. It is hardy to 0 degrees. Have you looked at http://www.beautyandthebamboo.com/? Good luck