On Tue, 17 Apr 2012 23:19:43 -0700, "W"
wrote:

I am building a hedge to the street with Photinia Red Tip. The young
plants are not really blocking much of the view. What are the pros and cons
if I plant double rows of plants, spacing two feet between each row, and two
feet between each plant on one row?

Since the plants would be back to back, the street facing row would get sun
in the morning on the street side, but would be denied sun on the back side
at all times of day. The lawn facing row would get no sun in the morning,
but lots of sun in the evening. I guess that means the inward facing parts
of both rows would die off over time. But would planting double rows
make the hedge thicker and block more of the view from the street?

If yours are a deciduous variety they won't offer much privacy
regardless how many rows you plant... if an evergreen variety one row
would be sufficient as they are a dense plant and usually grow quite
large and if in rows they will shade each other so the inside parts
will be bare anyway.