http://na.fs.fed.us/spfo/pubs/pest_al/hemlock/hwa05.htm
Here is the bug. I would not plant any more. I have 60 year old trees that will be dead in a year or 2 more. All the ones I have planted in the last 15 years have the bug. You can control it with sprays but very expensive and time consuming and who wants extra pesticides in your yard. It is wiping out the Hemlocks all up and down the east coast and Nova Scotia is hit hard too. A real shame as the Hemlock is a beautiful tree.
That web site said that the deer don't seem to care for the green giant arborvitae. Could be a sales ploy. They do eat Cypress. Deer will eat anything if they are hungry enough.
Dave I don't think the Emerald green is the same variety as the green giant. Green giant is a mix, thus faster growing. Emerald is slow growing and very common around here. Arborvitae is also called white cedar or northern white cedar too. Foot a year sounds right.
Stay away from those red cedars if you have fruit trees. Cedar apple rust. PIA.
Dave you may want to read this about cypress compared to green giant. You may change your mind
http://www.articlesbase.com/environm...ess-20970.html