Tall and skinny perennial plant?

Need ideas for a tall and skinny perennial plant/shrub (zone 4-5) which looks nice and can grow to 3-4 feet within 6 inches (width) of confined space - the length is about seven foot. The problem is there is only six inches of space available between a long paved walkway and an ugly raised and bare concrete porch (4 feet high). Ideally, would have just put stones there, but need to hide/cover the bare concrete porch wall a little. Cannot move walkway and not enough space to create a raised bed in that six inch of space. Any suggestions (even non plants/shrubs welcome).

Tall and skinny perennial plant?
I have a narrow strip 6 inches wide in between my front walkway and the garage wall. I planted delphiniums and they look great. They are a tall flowering perennial. I use purple, white and blue. This is one of the true blue flowers. Most delphiniums are great in zones 3-7. Most delphiniums grow 3 to 6 feet high. You can steak them to help support the large spikes of flowers. Keep them watered and cut off the spent spikes and you will have a beautiful display all season. A great book on plants %26amp; flowers is The American horticultural society encylopedia of plants %26amp; flowers. Great pictures and specifics of each plant. Good luck.
Reply:Have you considered an espaliered vine?


Or trompe l'oiel painting the wall? Or veneering the wall


with stone?
Reply:you will most likely need to plant 1 or more vines of some kind in such a small confined space. good luck