Hemlock is a beautiful tree, and I have seen hedges that have been hemlocks, they are normally large hedges, since the tree has to exhibit some growth.
Though I would keep an eye out for the Hemlock Wooly Adelgid, an introduced insect which is taking out hemlocks just about everywhere, except in places such as Maine, where it just gets too darn cold for em.
I'm not an expert on it, so I'm not sure if they found any resistant strains of Hemlock, but people may have a solution for it in the next 5-10 years.
Certain strains of Ladybugs, as well as japanese lady bugs are being bred to combat the adelgid, so far it seems promising.
"Wait.. his character is the last remnant of this elven culture?... Sigh*
Even though we hate him guys, we MUST protect the gene pool!"
I feel the same way about plants : )