Would you consider pruning the pieris? I would want it to be no taller than the railing. Since you need deer resistance, how do you feel about Korean boxwood?

Take a look at Cephalotaxus cultivars, a yew like plant that is highly deer resistant.

Thanks everyone for great ideas.

Laceyvail, how have you found the hardiness of Cephalotaxus? I've looked at it a few times, but been scared off by the zone 6 rating, and that I haven't seen it around here.

I don't know whether it thrives where you are, but I love skimmia japonica for those conditions. The blossoms are lovely but not real showy and if you get male and female plants, you will have beautiful red berries on the female bushes. The deer never even nibble on mine. I have had a hard time finding full size plants - the dwarf seem to be more popular, but they are not tiny.

mad_gallica--Re hardiness of Cephalotaxus. Some sites say it is hardy to zone 5 and I had one at my old property when I was certainly still zone 5. I know it came through one spell of minus 16 degrees. My name says zone 6A, but with climate change, I expect I'm now likely zone 7--winter temps haven't gotten below maybe 10-12 degrees in years with a once or twice dip to maybe 3-4 degrees. It actually rarely even gets into the teens even at night. I miss winter!

I've never seen it around here either, but you don't see much other than what can be purchased at Lowes around here. My new neighbors were astonished that plants could be purchased through mail order.

It sounds like it might be worth trying. We haven't had a 'real' winter in years either, but we seem to run about 15F colder than you do. So -15F is still a real possibility.