The HTA announced its bedding group last week, saying it would be complementary to the British Protected Ornamentals Association, the NFU associated bedding group.
Hartfield said: "This industry is too small to have organisations doing the same thing so it is disappointing that that potential situation has come about. The word 'complementary' would imply discussions prior to that information coming out, but that hasn't happened so it's a bit pre-emptive."
Paton said: "The HTA is a very competent organisation. It has the benefit of the National Garden Gift Vouchers. But there is no case for another bedding plant group in what is a shrinking industry."
Eleven prominent growers are involved in the group. HTA business development director Tim Briercliffe, who is due to meet BPOA chair Sarah Fairhurst, said: "We are just doing what our members asked us to. There is a gap for investigating the market and doing promotional work and that's what we are doing. I'm not looking to undermine anything that the BPOA does."