Speaking at a conference organised by the Garden Industry Manufacturers Association (GIMA), he said the "demise of the wholesaler" meant more direct supply and so relations between retailer and supplier were now "more important" than they had been in his 45 years at the garden centre.
Bunker said getting goods out quicker to garden centres was crucial, as was dealing with problems promptly.
He criticised hauliers for "letting us down" by not delivering premium deliveries on time.
Bunker said marketing people made him "fed up" because they did not say what a product such as a lawn food did in large letters on the bottle and because they used focus groups rather than their own eyes as well as changing product names pointlessly.
He said Paris Natar's Smart Garden was the best supplier. Bunker also called for a return to pre-season discounts and told suppliers not to put loyal customers on "stop" if they missed payment dates by a few days.
Also speaking was Klondyke's Bob Hewitt who said his 24-centre group now turned over almost £50m. The former Wyevale chief executive pointed out that group was now on its fifth chief executive in the decade since he left.
Since joining Klondyke he has concentrated on redeveloping existing centres since 2010, with seven redevelopments and two refurbishments, all including new restaurants.
Daleside is the latest, opening in July. He said restaurant sales could reach 25 per cent from 20 per cent by 2019.
Garforth begins a rebuild in September, planning is going in to develop Edinburgh, then Polmont, Weavervale and Holland Arms are next. Klondyke has disposed of four small centres and a nursery since 2008, with some going to discounters or housing.
He said in 2015, December was top month with 14 per cent of sales, followed by June at 13 per cent. Average spend is £18.55. Catering sales are £11.2m, gifts £7.3m, Christmas £3.8m, shrubs £3.6m and bedding £3.5m. Hewitt said there was growth in ready made plant sales, pets, solar lights (where there is a shortage of supply), houseplants, catering and cook shop.
David Yardley will succeed Hewitt at the end of the year. Hewitt will become chairman.
At the GIMA AGM, Chris Ramsden replaced Colin Wetherley-Mein as GIMA president.
See more in HW next issue.