[AnnieBL]

As others have already mentioned, spearmint is very invasive and if grown outdoors, it should be confined to a container or pot. In the UK, all the big supermarkets sell growing spearmint and cut bunches for not a lot - what you should be looking for will be labeled as "Mint" as in mint sauce, rather than Spearmint. If in doubt, just pluck a little bit of leaf and rub it between your fingers before smelling / tasting it.

It is my understanding that the mint most usually available and sold simply as mint is -not- the same species as spearmint even though visually similar. My wife, who detests the smell and taste of spearmint, would shudder at the thought of using it for mint sauce or other common culinary purposes, but is an extensive user of garden mint (which is just as invasive). I don't know whether garden mint is an AA.