New privet hedge?

Hmmm yes, just discussed this at length with my mum - the roots are about 12 inches long, so I sat thinking about how to get hold of so many massive pots and still have them regularly spaced in the trench... but she came up with a great idea!

Get a largish plant pot, cut the bottom out.
Wrap and tape a length of viscuine around the pot, so that the depth is about 18 inches.
Sit the pot covered in viscuine into the soil/horse manure/bonemeal.
Fill pot with soil/horse manure, etc (and the privet, of course).
Remove pot
Viscuine acts as a large pot - although bottomless, the moisture is still held around the roots.
In Autumn, remove viscuine 'collars' - no need to replant or anything!

What do you think? I'll keep them well watered