Yes, mums can get overwatered. When they are watered too much, the roots of the plant can become waterlogged and begin to rot. This can cause the plant to become stunted or even die. Overwatering is one of the most common problems people have with growing mums. If you think your mum might be overwatered, check the soil before watering it again. If the soil is still wet, hold off on watering for a day or two.