It's hard to know what might be going on, but mint is usually quite hardy. A few varieties, such as Corsican mint, are less cold tolerant. Peppermint is one of the hardiest. Was the area covered by mulch or fall leaves? If the soil was bare at any time during a deep freeze, it is possible that the roots have died back, at least somewhat. You might try keeping the area moist (but not waterlogged) and waiting a little longer to see if the plants recover. However, if you want to be sure you have some mint this season, you might add at least one more plant.
It might also be possible that your mint has been attacked by a pest or disease. Mint flea beetle larvae, for example, feed on mint roots (the eggs overwinter and the larvae hatch in spring). Dig up a small area to see if you can spot the roots and check their health. Look for holes in the roots, where a larva might be inside. For more information, see:
http://mint.ippc.orst.edu/mfbmanagement.htm
http://mint.ippc.orst.edu/rootinsects.htm
It's hard to know what might be going on, but mint is usually quite hardy. A few varieties, such as Corsican mint, are less cold tolerant. Peppermint is one of the hardiest. Was the area covered by mulch or fall leaves? If the soil was bare at any time during a deep freeze, it is possible that the roots have died back, at least somewhat. You might try keeping the area moist (but not waterlogged) and waiting a little longer to see if the plants recover. However, if you want to be sure you have some mint this season, you might add at least one more plant.
It might also be possible that your mint has been attacked by a pest or disease. Mint flea beetle larvae, for example, feed on mint roots (the eggs overwinter and the larvae hatch in spring). Dig up a small area to see if you can spot the roots and check their health. Look for holes in the roots, where a larva might be inside. For more information, see:
http://mint.ippc.orst.edu/mfbmanagement.htm
http://mint.ippc.orst.edu/rootinsects.htm