My mint is a very hardy perennial and is in my garden year round - however, it is terribly invasive and I need to thin it out constantly or it will take over the garden. I find the best way to keep it is to dry it. If you want a quick dry - place it on paper towels in the microwave and zap it a few minutes. It will dry right up and can be put in a screw top bottle or spice container immediately. Debbie - Spencer, MA ... View related article.