I would suggest violets (odorata). I've bought some good ones from bluestone perennials.com before.

do you have room for shrubs or wanting shorter perennials?
some hostas have fragrant blooms.
for shrubs, maybe burkwood's daphne or 'carol mackie' daphne or a witchhazel (can get large).
you might could get a sarcococca hookeriana var. humilis to survive in a protected area. said to have the best cold tolerance of the genus.

Here is a link that might be useful: fragrant hostas

Lily of the Valley, I don't like the scent much, but lots of people do.

Sweet Woodruff (if I remember correctly) does well in the shade. The leaves are very fragrant when cut or trampled, but I think I read somewhere that the flowers are fragrant too.

I have a clethra growing in a shady nook of my garden...It's blooms are my favorite scent in the fall. I strongly recommend it

www.worldplants.com sells hardy orchids. Some types prefer shade to full sun.
Paranoid, remmeber one thing..when plants are grown outdoors, a northern exposure is much brighter than plants grown indoors in a sunny window.

There's a few hardy, 'fragrant' Hydrangeas around. If you have an arbor or something that will hold a vine, Humming Bird vine is very prefusive..they might take over..I started one vine, and now they're growing in different places, including dark areas. Flowers are orange/frangrat.

Some lilies thrive in shady spots. StarGazers are my favorite, but I think they need medium to bright light. There's one Tiger lily, orange flowers, that's sweet-smelling. Toni

If you want fragrant leaves, consider some mints or lemon balm, which will do OK but not go crazy in that site, as long as they're regularly watered.

Other fragrant shady perennials include mitchelia repens (twinberry, a gem if you've got acid soil) cimifuga racemosa (bugbane), and either monardas or phlox might work in filtered sun.

Shady shrubs with fragrance include spicebush (lindera benzoin) buttercup winterhazel (corylopsis species and hybrids) and of course, the whole rhododendron family (rhodos, deciduous azaleas, and pieris japonica, although flowering may not be heavy under your conditions.

Jim

Beware, lily of the valley and sweet woodruff can be very invasive and they only bloom for about two weeks.

I just recently discovered that some hostas are very fragrant though you do have to get close to smell it.

My daphne odora drifts fragrance clear across the yard but transatlantica Summer Ice does not.

IF your north bed is really bright you might get Oriental hybrid lilies, north isn't enough for me in the northwest for them but they do drift fragrance across the yard.

My Sarcocca doesn't drift much but does grow in shade.