Once rooted mint spreads fast and if left alone can cover up entire garden. Best way is to grow mint in pot.
How to grow mint
Mint prefers moist and fertile conditions for growing. Soil should be selected so as it should be well drained, good water retaining and fertile.
Best way is get a plant from garden centre to start with. This you can use as source for baby mint plants. Plant it in large pot.
Keep your plant at a location where it receives enough sunlight but ensure soil doesn’t dry out. Mint likes humid conditions will dry if it doesn’t receive enough sunlight.
Once this mint plant develops few sprigs, you can use them to create new plants. Harvest these springs for your use.
Every year remove your plant soil and break it into 3-4 parts. Each part will create a new plant. Keep an eye on spread of your plant can spread to whole garden if allowed to grow freely
Using springs for planting
Cut longer springs from your mint plant and immerse it in glass full of water. After 7-10 days new roots start emerging from these springs. After these roots attain a length of few centimeters transfer them to pot.
I have grow mint from cutting click here to view