Armitage said there had been a lot more interest in Glee new products, adding: "There's more confidence in the market place so people are prepared to take a risk and something new."
He said retailers he had spoken to were "upbeat" about 2015's prospects.
Armitage and GCA chief executive Iain Wylie were interviewed by Radio 4's You and Yours, which is to broadcast a show on changes in garden centres and how they have broadened their offer in recent years.
Armitage added that any publicity was good for the industry. He said on the recording that broadening product categories meant garden centres had steady income year round and could pay rates and wages all year, rather than having to shut in the winter.