balkong, i'll tell you what i tried to keep on the balcony in winter. japanese yew - smallish, about 12" pot. overwintered twice/bloomed, then died 3rd year. hinoki false cypress - overwintered once. reg english ivy - died sev years when it was dropping into low teens; survived well last winter. this winter should be ok too - so hardy to 17F, sort of? it's in the biggest 18" pot. hydrangeas - overwintered once, but then bloomed very weakly. so not much point. montauk daisy overwinters well in 12" pot, burried in soil in 16" pot . so for me it's good. it even blooms 2nd year farely well. but then i chuck it, since it's weak. overwintered oriental lilies: stargazers once: wrapped the pot in big bubble and then covered with cardboard box overturned and lined in plastic. but easier to just dig in new ones in spring. oh, mums of course survive - but with NE sun won't really bloom. may be with your west sun corner they will fare better. that's about it for me. i had clematis on a diff balcony facing east/south-east. it did not survive winter though. also juniper survives, but it needs sun. may be SW corner will do. This post was edited by petrushka on Sat, Apr 13, 13 at 14:09

I think you might have trouble in the shed. Most spring bulbs originate from areas where the ground never actually freezes in winter, and here they recommend planting them extra deep, I presume because of our cold temperatures. I have done pots of crocus and small daffodils successfully, but that was kind of underground... we had a sprinkler system, and the controller for it was about a foot below ground level, up against the house, in a dug-out box where you lifted a wooden panel to gain access. So I put the potted bulbs in there, and covered it with the wooden panel, then let the snow mound over that naturally. Then in February or so I would bring the pots indoors for a pre-spring treat. Another method that has worked for me is to put pots of crocus bulbs in the back of the fridge, but that obviously cuts into food storage so isn't ideal.

i have successfully overwintered oriental lily in the 13"pot(about 9" deep) : 2 bulbs together with english ivy. i wrapped the pot in big-bubble plastic and set it inside an even bigger empty pot and put some mulch on top and overturned plastic dish to sort of keep the water off and trap the heat. but i am in zone 6 - i have it on north-east loggia that has no sun at all in winter, so no warming up, no rain. i was mostly afraid that they will rot and read that it's best to cover the whole top with clay saucer. i read in balcony forum that other people keep orientals in pots over winter outside successfully. the pots freeze completely of course. and this winter had some pretty harsh weather, colder then usual - i am in nyc metro area. but they are blooming very nicely now.

I have all of my asiatic and oriental lilies in pots, and in the ground. I have had to do this because of gophers stealing all my bulbs. They would suck entire plants down their tunnels, never to be seen again. I am in a much colder climate than you, but I have not lost a plant since. The bulbs have mulitiolied very well as a matter of fact.