These are just some suggestions:
-Helenium (here is picture of my 'Mardi Gras' which I just love. But they also come in all red or all yellow)

-Oriental Lilies back of border close to railing so you can smell them!
-Balloon Flowers also can add blue to the garden
-Bee Balm for red colors
-Hostas in front of border (can take morning sun)
-Bulbs for spring color
-Maybe an aster or mums for fall color
-Dark burgandy heucheras to compliment the gray house

I could go on and on, but I am sure others have some suggestions also!
Jen

Sedum looks good all year long.
Neat clumps of succulent leaves grow all summer. Then in late summer and into fall they flower in shades of white, pink, rose, red or burgundy. After they finish flowering, you can leave the stems w/seedheads stand for winter interest.

My favorite Sedum is 'Matrona', because it never flops.

Julie

Thanks for the suggestions!

Lisa