Known for expressing frank opinions on the BBC's 'Mary Queen of Shops', Mary Portas has headlined her talk "the brutal truth, garden centres exposed" and some industry members are worried her renowned catty style will damage the industry.
Portas is believed to be visiting Webbs garden centres among others.
GIMA director Neil Gow said: "It will be interesting to see what she has to say. I hope it is positive if it is going to get into the consumer press. What we need is positive PR If it is going to be negative we have to give serious consideration if it is right.
"Negative PR in the industry is fine if it is helpful in pulling our socks up but if it is in the consumer press it may do more harm than good."
Garden centre consultant Eve Tigwell said: "It depends who she goes to. We have some very good garden centres."
But New Hopetoun Gardens owner Dougal Philip said: "I hope she does [criticise us] because no-one is perfect. We all have weaknesses. Things move on so quickly and customers expect more and more. At the moment they want good knowledge and advice and solutions to problems and I don’t know if they are getting it from garden centres."