Nigel,
Barry has explained what a Weed Pot is, but I'll try explain a bit further.
In America (where turning is a more accepted art form) weed pots are a strange phenomenon. People collect them and display them with a twig, bit of grass and the like, almost like the Japanese art of flower arranging - Ikebana.
The idea of the Weed pot came over, now all we need are the collectors and arrangers.