I try to keep all my mint (spearmint and pineapple mint) in containers since it can be invasive. However I've noticed that the plants start to look ragged after the first year. They are never as lush and full. By year 3,they look even sorrier. Doesn't matter if I give them lots of compost or even Miracle Grow. So I'm wondering if I need to generally reseed my mints every year just to propagate for poor regeneration.
Thoughts?
I have a pot with spearmint buried in my garden and it managed to escape. in winter it grows well but we have no or very little frost.