long & thin (max 2' deep) plants for total shade??

I live in a narrow row-house that faces east. I have a narrow backyard (12.5' wide--and yes, that's also the width of my house) with 6'-high wooden fence on its north and south boundaries. Along the southern (north-facing) fence I have a ~25'-long bed that varies from 4' to 3' deep. The back 2' of the bed gets absolutely no sun. The house shades it in the east and my shed shades it in the west. The bed is interrupted about 2/3 of the way from the house to the shed by a small yew (5' diameter, 7' tall), and my compost bin, which sort of hides behind the yew. The soil is quite clayey and I can't seem to get lilies of the valley to grow in it, FWIW.

I have some nice violets, lungworts, tiarella, a hosta, a Japanese painted fern, pansies, bleeding heart. The trouble is that, even with the yew breaking up the length of the bed, the plants are dwarfed by the vertical expanse of fence. It's a nice silvery weathered wood, but I want to cover up at least the bottom 3' of it. However, I don't want anything wider than 2' or I won't have room for my current plants. Another limitation is that I'm excluding predominantly yellow and orange flowers and foliage from my color scheme.

I'm considering several options:

1. Vines on trellis. I already have morning glories and Boston ivy that grow on the fence, but they tend to be sparse at the bottom and try to clump at the top of the fence, where they get more sun. Will every vine do this? I'm interested in the following vines, probably several in combination:
-American bittersweet (celastrus scandens) [need male & female to get the berries]
-British honeysuckle / woodbine (lonicera periclymenum)
-calico flower / Dutchman’s pipe (aristolochia elegans)
-cardinal climber (ipomoea sloteri)
-clematis (shade cultivars: alpinas, macropetalas, Polish spirit, Montana Rubens)
-cypress vine
-moonflower “Meekerii” (ipomoea alba)
-passionflower
-potato vine / impomea [does it climb? or just trail?]
-rose (shade cultivars: “Alberic Barbier”)
-silver lace vine (polygonum aubertii)
-snail vine / climbing shell vine
-star jasmine (trachelospermum jasminoides)
-winter jasmine (jasminum nudiflorum)

2. Planters at the top of the fence with trailing plants. I have tried this before with petunias, but the problems are that the fence is kind of old and can't hold much weight and also that if I forget to water the planters for a couple of days, the petunias die back and don't get long enough to cover the fence. Maybe I should try again with plants that trail more, like potato vine, but I just have no idea what would work well.

3. Tall (3'-5') plants in the ground next to the fence. I'm not sure if such deep-shade-loving plants exist. It seems that the potentially taller shade plants that I've tried, like bleeding heart and Solomon's seal, don't grow as tall when they're in total shade. Others, like the mint that I put next to the compost bin, lean forward into the semi-shade area, trying to get to the sun. Others are said to be very invasive. Please advise as to whether any of these could work:
-astilbe [does it get tall enough?]
-bugbane
-goatsbeard
-gooseneck loosestrife
-hardy grape leaf anemone (anemone tomentosa)
-hart's tongue fern (asplenium scolopendrium)
-hellebore [but I think they're kind of drab-looking]
-Jacob's ladder (polemonium)
-lady's mantle [if there is a non-yellow variety]
-tall meadow rue
-tobacco plant (nicotiana sylvestris)
-ostrich fern
Also found this list: http://www.architecturalplants.com/pigeonholes.dense_damp_shade.html

4. Shade shrub or dwarf tree that can take being espaliered or severely pruned back to 2' deep. I have no idea what would qualify. I like maples, camellias and Caroline allspice. I'm not keen on azaleas or rhododendrons.

5. Vertical/sideways garden of little plants in some kind of rack-like structure. I saw this done in the Chicago Botanic Garden. They had lots of little wooden "pigeon holes" filled with dirt, and the plants grew out of the holes by a couple of inches. It looked a lot like this cabinet http://www.officemuseum.com/IMagesWWW/1892_Pigeon-hole_cabinet_illustration.jpg , but the holes were diamonds rather than squares. I would have to be careful that whatever I built would be stable and not deteriorate the fence, either with water or weight, as I would presumably anchor it to the fence. Here's a picture of similar gardening structures: http://www.401richmond.net/building/eco.cfm

6. Combination of any of the above.

What do you all think?

Ruth

Have you considered cast iron plant, also known as 'aspidastra'? It is a definite vertical (non sprawling) dark green strappy leaves and requires, repeat, requires shade.

Some kinds of Ligularia grow that tall. You'd have to ask the places that grow it how wide it gets but the height is there. It says semi shade but I grow mine in full but bright shade and it works. They have yellow or orange flowers but I just cut them off before they bloom because I don't like daisies in my shade garden.
http://www.bigdipperfarm.com/cgi-bin/searchstuff.pl?Botanical=Ligularia

The Dixie Wood Fern (Dryopteris x australis) will grow 4 feet tall and the Dryopteris affinis 'Crista The King' (Male Fern) grows 3 feet tall. They look beautiful in mass. In fact, go to the Big Dipper site and put Dryopteris in the search engine there. There are quite a few upright and tall ferns. I think that ferns make a great background cover.

I love to go to the website of Big Dipper Farm when I'm looking and you can search by shade or sun or semi shade and they have some great ideas.

As to (3), many of the plants listed there don't grow to 3 feet tall. There is a variegated hellebore available at Lazy S farm, but again probably 2 feet max. Astilbe will get that tall if you buy the right cultivars. 'Superba' will grow 3-4 feet tall but of course that's including the flower. I leave the flowers on my astilbes though.

As to vines, star jasmine in full shade looks fairly ratty. I grow Clematis M. Rubens under my patio eaves and it does very well there. I like M. Broughton Star a little better. The flowers are larger and it has a stronger fragrance. If you train them to the top of the fence they will eventually drape down and cover it. They are very big vines though. And I think that a passionflower would be fine too. Mine are only in partial shade though.

Espalliered camellias would be fine and evergreen. Camellias can grow in the dark. I'm rather fond of sasanqua camellias. They are easier to grow than the japonicas and are easy to train.

Hope that this helps a little.

I had a five-leaf akebia which did well along a fence with very little sun--finally had to cut it out since it did a little too well and started swallowing other plants farther out from the fence. The polygonom silver lace vine you mention can also be a thug, but might be controllable in your no-sun zone. I also had to rip out some goatsbeard which reseeded itself all over a shady bed.

Did I see gooseneck loosestrife?? I don't know about your area, but it is invasive big time here. It sends out runners and pops up in the middle of other plants. Pulling it up would seems easy, but it defies getting all the runners and just keeps popping up. Pretty flower, but hardly worth it. I suppose that some people bury the pots, but then there's possible reseeding.