"Sweet Mint"? Not familiar with that one here. Could it be also called "eau-de-cologne mint"? There is a "pineapple mint" which should make a nice garnish.
I like to keep at least two pots of plain mint going and regularly cut one down to ground level. If mint is allowed to get too old the leaves become very tough. It's the fresh young shoots that are best and mint is a voracious grower.