One good mask is to take chicken wire, spray paint it in a flat black or flat dark green (you dont want it shining!!) and wrap it around your plants. This severely distorts the image of a plant when looking from a distance...and it doesn't block light!
left photo is from about 25' away and you can barely make out the wire fencing.
right photo shows plant in foreground at 2' and background at 4'.
hope it helps
