Guests included All Party Parliamentary Gardening & Horticulture Group secretary Brian Donohoe MP as well as Beechgrove Garden presenters Jim McColl and George Anderson.
Chief executive Carol Paris said: "We always should have been here and having a Scottish president this year in Stan Green and Simon Fraser (Ben Reid Garden Centre) as a council member." The HTA will return to the show in 2015, she added.
Paris met the Scottish Retail Consortium to discuss regulations including the Agricultural Wages Board, which has been retained in Scotland after abolition in England and Wales, making it "difficult for Scottish growers to remain competitive".
She also discussed licensing laws based on rateable values, meaning some garden centres pay more than pubs.
Green said the HTA is "not taking sides" in the independence debate. "If Scotland was independent it would affect business - we're a net importer of horticultural produce," he added.
The RHS was also at the show as horticulture bodies sought to shore up membership ahead of the vote.