Window boxes for shady area

[abstibus]

Tomorrow is Feb 1, thank goodness, and my thoughts are already running ahead to the time when I can think of window boxes. The problem is that one window only gets the early morning sun, as it's in what is called the 'remove' area of the house and faces a blank wall about 5 feet away.
Can anyone suggest any window box plants that might be OK for there? I live in a town house and although I would love to have lots of tubs outside for the summer, my dog keeps digging them up.
Many thanks.

[coccinelle]

Dwarf bizzy-lizzies or pendula Begonias would be fine. The first are annuals and the second are a kind of bulb so would flower year after year but you'd have to dry them off over the winter.

[rowanwitch]

variegated ivies, smaller ferns, white bizzylizzies and maybe a few spaces for short term seasonal lodgers like pre grown miniature bulbs or pansies

[abstibus]

Coccinelle and Rowanwitch - thanks for your advice. Sorry for the delay in replying.
A-M