Why use should I use Topiary Shears? 

The tool I have chosen to clip the box shapes with are the topiary sheers. Based on the design of traditional sheep shearers, these light weight and smooth action sheers are held in one hand and used to lightly clip this year's growth. It's such a nice, relaxing job to do, and because they only remove a little at a time, there's no chance of slipping up and disfiguring the topiary bush too severely.
Work your way slowly around the plant, standing back to assess and maintaining the shape as you go. I grew a box spiral from a cutting about 10 years ago (inspired by one Alan Tichmarsh did on Gardeners' World) and its now about there.
Once clipped, feed with a general purpose organic fertilizer and water well if dry, especially if growing
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