Gardner moved to Forest back in January and became a key player for the Reds, playing 18 times for the Midlands outfit.
That was his second loan spell of the 2014/15 campaign - after he moved to Brighton and Hove Albion for the early part of the season - and he says that he has been very pleased with his personal development.
"Forest was good," he enthused. "Everything was top notch. I was playing every week. I was scoring goals. We were winning. That was superb.
"I enjoyed both loan spells immensely. My goal at the start of the season was to get over 30 games. I have been happy to achieve that. I have been really happy with the season I have had."
During Gardner's time at Forest, he thrived after being utilised as a defensive midfielder by Dougie Freedman.
Regularly on the scoresheet, Gardner also did a great job shielding the Reds' defence and his performances made him one of the standout players in the Championship side's squad.
It is doubtful that he will go back to the City Ground next season, though, as Villa boss Tim Sherwood is likely to want to bring him into his first-team.
Sherwood is always keen to give promising youngsters a chance, and Gardner will be hoping to benefit from his appointment.