The former RHS show exhibitor and owner of Glebe Cottage Plants, whose six-part Life in a Cottage Garden series began on BBC2 last week, said gardeners should propagate more of their own plants.
"Look at the profile of a plant you might buy in the garden centre. It may have started off as a cutting in India or China, then been sent to Holland to be grown on under huge arc lights, using masses of fuel and loads of water," she added.
Lowaters Nursery director Charles Carr said: "We propagate as much as we can but plants are generally imported for a good reason - they may be difficult to propagate here. Quite a lot of lavender comes from Israel because they have a better environment for it."
Writer Peter Seabrook said: "Isn't it time the BBC had one spokesperson from conventional gardening now Carol Klein has gone with Monty Don? For Klein to bite the hand that fed her for so many years is outrageous."
Don, Klein, Joe Swift and Rachel de Thame are the new Gardeners' World presenting team, with Toby Buckland and Alys Fowler dropped.
Don, who will present from his own garden, said: "I have the gardening kit I need, so we will not be buying any more, and if something breaks we will mend it."
Hayloft Plants director Derek Jarman said: "They don't help the trade. Both Don and Klein are a bit out of touch with reality."