I don't know if Moring Glory are poisonous, but they are thriving on the railing of my (directly) north facing, always seemingly shaded balcony.

I have thick 1"x1" railings and once I led the morning glories to the railings, they have had no problem growing up them.

I'm sure the Painted ferns are fine for plants.. I've never heard anyhting to suspect they are other wise... ferns in themselves are fine as they are eatten as fiddleheads.. lightly sauteed in butter... good eatting...
As far as a shade vine.. morning glorys are so tollerant.. and so well without alot of sun.. I'd think many vines might also.. find one you like and then see how long you can keep it going.. Gordon

um.... i read sometime fiddleheads are poisonus as they grow up.
i'm not sure how poisonous they are, but i remember reading it somewhere and thinking- how strange.....

Morning glory is poisonous. Most cats don't eat poisonous plants though, and there are things you can do to deter them if you are so inclined.

Anyways, I have an east-facing balcony, and the MOST shade-tolerant things I have found are english ivy (by far the winner), lobelia, many houseplants, ferns, Dichondra 'Silver Falls', hostas, primroses, etc. Thunbergia is the most shade-tolerant climbing vine. Common name is black-eyed susan vine. There is also a blue (purple) flowered variety. Ivy could be trained to climb, and if you chose the right variety, you could probably even overwinter it in your zone!

Did you check out sahoyaref's pics? Very nice, bet there's not much sun there either. - Our black eyed susans did better than ever this year, and we had them in the shade.

thanks for all the help!
I wasn't sure if morning glory was poisonous or not - thought maybe it was just the seeds, but my cats will eat almost anything if given half a chance and I'd just rather not have to worry about it.
I will try to get some of the plants you mentioned,sahoyaref. Right now, I have some begonias and a pot of lemon balm that seem to be doing ok.

thanks again!

I know that clematis can grow in the shade. I'm gardening with Bamboo, who is always eager to chew on my plants.
My balcony can be burned by sun at some times during Summer. But on the shaded corner i'm growing :
Red ruby chard, nasturtiums, ground cherries, tayberries, raspberries and Jerusalem artichoke (using it as a fence). And I'll move my kiwi vine there too.
If you want to plant a vine and are in a hurry Dutchman's pipe is a fast grower. And runner beans and pumpkins are favorites for me : growing fast and I may change my mind next year and plant something else.

Here is a link that might be useful: To my balcony ...

how about cat grass? or catnip... mine seem to do ok on the porch and the cats might enjoy them.
Michelle