For what it's worth, I noticed you are zone 6, also. Eliot Coleman (from Maine) has some great books on Winter Harvest..maybe check the library. Notice it is "harvest" not "grow" in winter. I have had success sowing lettuce on March 1st and could harvest it by April under plastic when outside it was still freezing at night. It is amazing how warm it can get in there if the sun is shining, but you loose that heat overnight. My night time temps fall to below zero regularly over the winter and I still have edible leeks, green onions, garlic shoots, kale, carrots, parsley, and lettuce under plastic. My strawberry plant leaves are still green and alive, though not producing fruit right now. It's not so much the temps, but protection from the wind and elements I have found that make the difference. Also, selecting cold hardy lettuces and knowing when to plant them for winter use..similar to planning a fall garden. The trick is to pull the plastic really tight so the snow slides off. If it sags anywhere, then it spells trouble. My frame is made from PVC, using an up-cycled old deck as a "floor" on one section. This post was edited by pghgardengirl on Fri, Feb 15, 13 at 18:27

Thanks for the generous suggestions, everybody. bubba62, I'm concerned that you're right about bletillas and hellebores (especially the caulescent ones) not getting enough sun to flower in areas like what I'm working with, and neither genus has a lot of ornamental value without flowers. Iris japonica is an excellent recommendation and a good example of exactly the kind of tip I was looking for. It's a plant that I've never grown in my yard, but that I've always admired elsewhere. I think it will provide nice semi-evergreen foliage, occasional flashy flowers, and kind of a spreading groundcover effect, even in dark shade. Cool. I also agree with your assessment of Illicium henryi as a choice selection, but unfortunately, I don't know of any nurseries around here that offer them in anything larger than 3-gallon pots, so I'll probably have to stick mainly with my old standby, I. floridanum 'Halley's Comet.' Tricyrtis, Saruma, Asarum, Disporum, Disporopsis, Speirantha (my favorite), Trillium, etc., etc., etc. are all worthy suggestions, but for now I think I'm going to focus just on larger, more substantial plants as I lay out the structure of the new beds, and then go back later and fill in the gaps with smaller little perennials like those. jeff_al, I agree completely about Pachysandra procumbens, although I find its slow spread almost as frustrating as the aggressively rapidity of P. terminalis. Still, a better all-around choice, and I've put it on my list. ncdirtdigger, leatherleaf viburnum is another great example of exactly what I was looking for with this post. It's another plant that I have never grown and had sort of forgotten about, but I have seen it prospering even in very heavy shade. And I think it's really pretty, too, although I've known some people to be repulsed by the droopy, wrinkly texture of the foliage. Aucubas were already on my list, but definitely worth another mention as indispensable elements of the deep shade landscape in this part of the country. I'm not sure if winter daphne will get enough sunlight to flower in any of the areas I'm working on, but I love it so much that I think it I'll give it a try. If nothing else, I know that it's one of the few shrubs that won't be bothered at all by the extreme root competition that it will face from the maples and sweetgums in the wooded portion of the new beds. birdannelady, aren't fatsias terrific plants? I can't imagine having a dark, shady garden around here without it. I've already bought and planted two in my new beds, and may get more as the layout continues to evolve. Which variegated osmanthus do you have? My usual go-to favorite one is 'Goshiki,' which is gorgeous in light to moderate shade, but loses a lot of its color in heavy shade. Maybe other variegated varieties are better-suited to these conditions. What kind of acanthus are you growing? I like acanthus, but I don't really think of them as plants for dense shade. But I don't have a lot of experience with them, and I haven't really experimented with them very much. You're also exactly right about competition from tree roots being as big a problem as the shade itself. And I too have faced the catch-22 of the situation where each and every thing that we as gardeners do to provide good conditions for the roots of the plants we plant (soil amendments, fertilizer, supplemental watering, etc.) also end up promoting the roots of nearby trees to invade the hole and compete with your new plant. Some trees seem to be particularly bad (magnolias, river birches, and the worst: red maples), but most trees pose this problem more or less. It's a conundrum that I've never solved if you have any tips about how to cope with that paradox, I'd love to hear it. Nonetheless, I'm a big fan of edgeworthias, too, and in fact I bought one the other day for the new bed. Hopefully I can find a spot for it where it'll hold its own. Anyway, thanks again for all the help. I've begun acquiring some plants, but I continue to add to my list of others to consider for inclusion. In a lot of cases, I think the thing to do is just to find which plants will work there through some trial and error. But if anybody has any more suggestions or tips, please keep 'em coming. I really appreciate it.

How about a mix of magnolia grandiflora, ilex opaca or 'Savannah Holly' which is an evergreen hybrid of i. opaca and i. cassine, eastern red cedar, and whatever pines do well in your area? Sherry

I believe Emerald Zoysia will do fine. If you can wait until spring....thats when I would do it. I did mine in the middle of summer but got lucky because it was during a very wet period with lots of rain. I laid every single square myself and was very anal about making sure they were down correctly. BTW...there are many on this site that know a whole lot more about this than I do and I am sure they will chime in about what grass would work best.