Very few plants can withstand constantly soggy soil conditions. In fact, in most cases, plant roots that remain in soggy soil will start to rot which is appropriately called "root rot." As the roots decay, they turn brown and slimy and can no longer absorb nutrients for the plant. Although your plant may look like a goner, you can reverse the root rot by watering the sick plant with a mixture of hydrogen peroxide.
Stop watering the plant and wait until the soil dries out completely to the touch. If the plant is potted, place it in front of a fan or move it outdoors to speed the drying process.
Fill a pitcher with a mixture of 1 qt. of water and 1 oz. of hydrogen peroxide. Stir the mixture up with a spoon to combine.
Water the soil under the plant with the hydrogen peroxide solution until the soil is damp to the touch, but not soggy.
Allow the soil to dry out to a 1- to 2-inch depth before adding more of the hydrogen peroxide water. Continue using the hydrogen peroxide water for as long as needed until the root rot goes away.