I have a tiny inner city garden, split into 4 sections. I want something evergreen for one of the sections, shoud I think hedge, or will I lose too much plantintg space? Area is approx 7ft x 5ft, triangular. Whole garden faces directly North / South, so this section is shadiest part. Plant must not have poisonous berries. Also can't afford too much height (3-4ft maximum);garden style is 'cottage' Help!