As of Saturday, the Bowelbabe Fund for Cancer Research UK had reached more than six and a half million pounds in total.
Delighted with the results, the mum - who has been receiving end-of-life care for bowel cancer - said it was “bonkers” her T-shirt had now raised half a million pounds since going on sale.
She wrote on her Instagram stories: “I cannot believe that this T-shirt has now raised 500k for the Bowel Babe fund - half a million pounds!!!
“That’s bonkers!!! Thank you to you and In The Style for making all this happen.”
It comes after her private visit to the Chelsea Flower Show to see the rose which was given her name.
She said she was in tears when she heard the news and hopes her daughter Eloise could have the special flower in her wedding bouquet one day.
“I just can’t wait for my family to plant them everywhere this autumn,” she told The Sun.
“What breaks my heart and brings me the most beautiful thought, is that this variety can be grown for ever, and maybe one day even Eloise might choose to have it in her bouquet.”
Dame Deborah was recently honoured with a damehood by the Duke of Cambridge at her home for her “tireless campaigning”.
She has also written a book How To Live When You Could Be Dead which she said she is “gutted” she won’t be alive to see it published.