It would be tough to grow anything sizeable in a 1 ft planter. Have you thought about espaliered trees? They won't hide the view of the house much but they're so interesting you may not even notice the neighbor.

This may be too big for your planter but check out the link below and click on the top image to see it better.

Perhaps there is some other fast growing shrub that can be grown as a tree and still fit nicely in your planter.

Here is a link that might be useful: Ligustrum japonicum grown as trees

Sky pencil holly maybe work.

Chamaedorea seifrizii or Chamaedorea costaricana are thin-trunked, clustering palms that resemble bamboo, but don't drop near as much litter. I don't know what your weather is like, but seiftrizii can take a lot of heat. The Podocarpus and Pittosporum will do, but you will be committing to a lifetime of trimming.

I second Catkim's suggestions , especially the Chamaedorea . I love the look of palms around a pool as it transports my mind away to far off tropical islands.
( If you can't afford a trip to Bali , then create it in your own backyard )

Another choice for you to research is a woody vine called Grewia ( lavender star flower ) It grows great in narrow spaces and against a supporting structure.
I have one espaliered against my brick chimney where the planting bed is about 12 to 14 inches wide.