Titchmarsh, 65, who has been replaced by Monty Don, said he was offered a lesser role for the much-loved event after three decades as host.
The former Gardeners' World presenter said he was not bitter and had moved on.
But he admitted: "Yes, I suppose I was hurt, because I know people enjoy you doing it as much as I loved doing it.
"But they probably felt it was time for a change and may well be right."
It was announced last year that Titchmarsh was leaving the show, with the BBC saying in a statement: "The way the Chelsea coverage will be presented across the BBC has changed for 2014, and Alan decided to step away from next year's show."
Titchmarsh said: "I was disappointed but I'm not a grudge-bearer. You have to move on. Nobody owes you a living."
The chat show host denied that his replacement's lack of horticultural training - Don is a self-professed "amateur gardener" - bothered him.
"Presenting is a skill in itself. I've presented programmes on classical music, nature and the royal family. I don't hold Monty Don's lack of training against him," he said.
Titchmarsh, who was succeeded by Don on Gardeners' World when he left in 2002, added: "He's passionate and he gets through to a lot of people. Good luck to him."