On Feb 4, 11:59*am, mike wrote:
edit: *I might even try 2 foot *spacing on center.

I might rethink that :-) 'Green Giants' are hybrids and only
tangentially related to standard arborvitae (Thuja occidentalis).
Their typical spread is more closely related to Thuja plicata (one of
the parents) and can reach 25' - they are not by habit columnar and
narrow in profile, but rather more of a 'Christmas tree' shape - more
or less conical and broad at the bottom and with a tapering tip. Too
close a spacing will result in heavy shading and die out of lateral
branching and you could end up with a very spotty looking privacy
screen. Recommended spacing for a dense screen is 5-6' o.c.,
otherwise, 10-12'.