Western red cedar is Thuja plicata. Eastern arborvitae is Thuja occidentalis. See the link. Also, google Thuja. Eastern arborvitae requires water all summer long. Thuja 'Green Giant' may require more water than Thuja plicata; I'm not sure. Someone with experience with this plant should be consulted. Thuja plicata likes to grow in wet areas, but will live without summer watering once established.

I have deer and elk in my neighborhood. They will chew the fresh growth and damage the bark on many different kinds of young conifers, including Thuja plicata. I haven't seen much damage on Western hemlock (Tsuga heterophylla) or incense cedar (Libocedrus decurrens).

I have found that retail nurseries have little knowledge of native plants. There is a risk that they will tell you what you want to hear, to get the sale. I think your best bet is to ask questions here, and use google. If you have a soil conservation agent in your area, they are often very knowledgeable.

Here is a link that might be useful: wiki link.

ALL arborvitae are Thujas. Western red cedar is of course not a cedar at all (Thuja plicata) and is sometimes referred to as "giant arborvitae". While any thuja, and especially young ones, could be subject to deer browsing, the American or eastern arborvitae, Thuja occidentalis, is typically considered most prone to this, even to the point of being called "deer candy" :-) And it's been my experience that ALL types of arborvitae require similar growing conditions in this area. Although American arbs grow naturally in very wet conditions (also sometimes referred to as "swamp cedar"), they don't require it, are amazingly adaptable and once established, can be remarkably drought tolerant ("tolerates soils that are poor, rocky, clay, compacted, dry, and of various pHs extremely well, and is very urban tolerant to heat, drought, humidity, and pollution; however, not tolerant of shady situations"). I know of many established AM arb hedges that thrive with only natural rainfall, much the same as the WRC's or Green Giants or Leylands. Regular watering during the period of establishment is of course advised for any new tree planting.

Scraggliness result of suboptimal site conditions, with both species. Moister. more fertile sites produce denser, more attractive crowns.

Here are a couple of interesting quotes from the link below:

"Although not drought-tolerant, 'Emerald Green' arborvitae does fine in full sun"

"Its cold hardiness makes 'Emerald Green' arborvitae a solid choice for Northern landscapers, who might otherwise use Leyland cypress, a favorite in zone 6 and higher. 'Emerald Green' arborvitae would also be the choice over Leyland cypress in cases where a tall tree would be inappropriate. Whereas the latter reaches at least 60' at maturity, 'Emerald Green' arborvitae usually reaches just 12'-14'. These differences notwithstanding, the two trees have a similar look and are both popular, particularly as "living wall" privacy screens."

Here is a link that might be useful: arborvitae link

There is no cultivar 'Emerald Green' (in single quotes), the plant is from Denmark and named 'Smaragd'. Emerald (or emerald green) is a translation of the cultivar name rather than a cultivar name. The tree is a compact column or sometimes lower and broader. The Leyland cypress can be quite broad and open on some sites, it is not always columnar. It is already known well above 60' tall; the arborvitae I would expect to see at least double the heights given above. I have seen it in nursery rows as tall as nearby 'Fastigiata' ('Pyramidalis') assumed to be of similar age. The latter has been measured 43' tall here in WA.

Thanks to all. I think I am finally getting a handle on the different options but I still have some conflicting advice. It seems that "Green Giant" isn't available in this area. As someone mentioned, when you go to a nursery, the staff try to sell you what they have, rather than explaining why varieties perform differently. Yesterday, I spoke to a vendor at our local farmers market who told me that "Emerald Green" is the variety of Thuja that get eaten the most around here, and that Excelsior is the one she would recommend. I'm planning to check her nursery tomorrow and find out if Excelsior is the only one she carries....The hunt goes on.

I've seen stock labeled 'Excelsior' one time down here; probably it is a mistake for 'Excelsa'. Hedging types of western redcedar appear to be quite mixed up in local commerce, there may be several different cultivars encountered under any particular cultivar name.

'Green Giant' is a less lovely hybrid of the native, making planting it here somewhat pointless (except for collectors). In other regions it enables gardeners to have a facsimile of our local tree.

I certainly would not move mountains to get it for hedge or other general landscaping use in BC.

There is no 'Emerald Green' variety, the plant so-called is 'Smaragd'.

Sorry, I typed the name without looking, you are certainly right, Excelsa is the name. I'm even confusing myself now! I have seen Smaragd at out best nursery. Big Box stores have "Emerald Green". I'm still working on it, so thanks again. I appreciate everyone's help.

Dotty, how much width are we dealing with between your driveway and property line?

Everyone has their own opinion of course :-) Why GG's are considered "less lovely" than WRC's is a bit of a mystery IMO and they are often utilized here in place of WRC (or Leylands) for screening/hedging purposes because they do not grow as large as either of those two, they grow fast and they are very well-adapted to this climate. But if not available locally, then obviously something else will need to suffice. 'Excelsa' is a good choice, as it does not reach the potentially enormous dimensions of the native species and has a very dense and uniform appearance......in fact, I find it very similar to the Green Giants in both size and appearance. But not growth rate :-)

Influence of Standish arborvitae half of cross apparent in foliage of 'Green Giant'. What constitutes 'Excelsa' will probably not be the same from all outlets. I have noticed that a form I have encountered under the name here bronzes readily during winter.

I see no reasons to expect either of these to remain small trees.

"To 60 feet tall with a 12-20 foot spread at
maturity"

Here is a link that might be useful: The U.S. National Arboretum presents Thuja 'Green Giant', a large, evergreen sentinel in the landscape.