Ashton went on to score three more with Mark Cueto, Mike Tindall, James Haskell and Danny Care also crossing while Fabio Ongaro grabbed a consolation for the visitors.
England took advantage of Italian missed tackles with Luciano Orquera responsible for at least two tries.
And hooker Leonardo Ghiraldini endured a torrid time in the lineout as he consistently failed to hit his jumpers before making way for Ongaro.
"Against Ireland we won 12 out of 14 lineouts and today I think out of 12 or 13 we lost eight throws," said the South African Mallet.
"When you're giving away first phase lineout ball as easily as we did you're giving England a lot to attack.
"I never thought that we would play a game like we did today after the past two weeks and I never thought we could be so poor in the one-on-one situations.
"I know we can play better than that and we're looking forward to trying to put it right against Wales. Certainly it's a very unhappy dressing room and I'm a very unhappy coach."