Yesterday, while looking for something else I came across this discussion under the heading 'Mountain Bamboos in Gardens' in the 2000 Timber Press book THE GARDENER'S GUIDE TO GROWING TEMPERATE BAMBOOS by Michael Bell: "Although they are cold, damp and misty, the homelands of these bamboos are often much closer to the tropics than are our temperate gardens, so sometimes these species require a higher light intensity than we can provide, and sometimes a cooler or more humid summer, too. Also it should be remembered that species from tropical latitudes which experience cold conditions usually do so on a daily basis, whereas those from colder latitudes do so on a seasonal basis. This means that they do not experience very cold soil temperatures or long periods of dormancy induced by months of cold."

If you've been getting rain, stop watering. Too much water can cause the roots to rot. Are you fertilizing too? Having critters munch the leaves, shoots, and even culms is normal, but with really small plants you may want to provide some protection. Leaf munchers: snails, caterpillars, birds (I've seen finches eating the not-yet-opened leaves), rabbits, deer (might taste a few). Shoot munchers: caterpillars, rabbits, squirrels, deer (again, just a taste). Culm munchers: woodpeckers (not really munching, but they still make holes). You might want to think about covering your rufa next winter. I'm surprised it got topkilled. Was it really tiny, or planted late in the fall?

I used to grow my Fargesia in an area receiving noon and pm sun (to create a screen). They were not happy so I moved them to dappled AM sun--big difference. Fargesia and other mountain bamboos have a bit of an issue with high heat (especially at night)--one reason they have problems in the southeast. It has just been too hot to the liking of these mountain bamboo and your exposure sounds hot. You may have to go with a differ plant screen in the current area and relocate the Fargesia to a shadier/cooler locale. In the area that I originally had the bamboo in, I decided to put in a fence and then establised a hedge of boxwood. Good luck!

I don't think you have anything to worry about. I planted 2 10-gallon fargesia rufa, which I'm assuming has similar cold tolerance to robusta, in my yard here in southern Michigan. The coldest we've got is somewhere between 14 and 20 degrees, and the ground has already froze a little, although it thawed out also. Anyway, they're not quite as green as they were when I bought them in September, but they're doing well. Some leaves are a little yellow, but its holding them nonetheless.