First, what zone are you in?
In the absence of knowing that right now, all of the following suggestions assume you're in something like USDA zone 4-6. If you're further south there are more options.
If you want azaleas, make sure you can provide the acid humusy evenly-moist soil they need, and recognize that you will probably get a bit reduced flowering if they get that much shade. They'd still look nice though, so if your soil is right and you can water them as needed, go for it. They'll restrict you to mulch or a very easy-care groundcover like sweet woodruff, though, since you don't wanna be having to dig or cultivate anywhere around their roots.
Roses you have borderline too much shade for -- if you want to try 'em, research your cultivars verrrrry carefully and pick something known for shade tolerance and resistance to fungus diseases.
Other options:
If you want a kind of loose, country-style informal look, consider a row of bridalwreath spirea (the big ones - S. vanhouttei) along the porch foundation. (Tastes vary, but I really like them - nice shape, pretty white flowers in spring, nice colors in fall, can't kill 'em with a stick). Or a row of modest-sized hydrangeas if you like that. If you want a large shrub for the corner, something like snowball bush (Viburnum opulus 'rosea') or a big peegee hydrangea might work, just keep them pruned a little so's not to overhang into the porch. Or a yew, allowed to grow both out and *up*, might look nice at the corner. Or for something lighter and airier at the corner, perhaps a pagoda dogwood (Cornus alterniflora), or a 'real' flwoering dogwood for that matter if blight is not a big problem in your area, or an amur maple if you want to wuss out and go with something really hardy. With any arrangement of the above shrubs/trees, you could face them with things like daylilies, yarrows, etc.
If you don't want anything as high as the porch railing, just smaller things, daylilies are always good. You could probably get *some* blooms from a small lilac such as little-leaf or 'palibin'. Some clematis varieties would do well there, as long as you put a rock or heavy mulch over their roots... you could plant, say, 3 along the base of the porch and have little trellises for them to climb up. or if you like yellow, C. tangutica will take over the whole front railing and give you little yellow flowers and fluffy seedheads from early summer thru fall.
There are a LOT of perennials to choose from that would be suitable, although some of them such as peonies you might not want right there where you have to look at the dying foliage in the late summer or fall.
So I dunno, maybe you can find something useful in the above; if you decide more exactly what sort of plants you're looking for, we can probably make more specific suggestions.
Have fun!
Pat
